Characterization of non-biological polymers using flow-injection analysis with light-scattering detection

ABSTRACT

Rapid characterization and screening of polymer samples to determine average molecular weight, molecular weight distribution and other properties is disclosed. Rapid flow characterization systems and methods, including liquid chromatography and flow-injection analysis systems and methods are preferably employed. High throughput, automated sampling systems and methods, high-temperature characterization systems and methods, and rapid, indirect calibration compositions and methods are also disclosed. The described methods, systems, and devices have primary applications in combinatorial polymer research and in industrial process control.

This application is a divisional application of U.S. patent applicationSer. No. 09/285,335 filed on Apr. 2, 1999, now issued as U.S. Pat. No.6,175,409 to Nielsen et al., which claims priority under 35 U.S.C. Sec.119(e) to U.S. Provisional Application Ser. No. 60/080,652, filed Apr.3, 1998 by Safir et al., which is hereby incorporated by reference forall purposes.

This application is related to the following U.S. patent applicationsfiled on the date even herewith, each of which is hereby incorporated byreference for all purposes: Ser. No. 09/285,393, now U.S. Pat. No.6,265,226, entitled “Automated Sampling Methods for RapidCharacterization of Polymers”, filed Apr. 2, 1999 by Petro et al.; Ser.No. 09/285,333, now U.S. Pat. No. 6,260,407, entitled “High-TemperatureCharacterization of Polymers”, filed Apr. 2, 1999 by Petro et al.; Ser.No. 09/285,963, now abandoned, entitled “Rapid Characterization ofPolymers”, filed Apr. 2, 1999 by Safir et al.; and Ser. No. 09/285,392,now U.S. Pat. No. 6,294,388, entitled “Indirect Calibration of PolymerCharacterization Systems”, filed Apr. 2, 1999 by Petro et al.

BACKGROUND OF INVENTION

The present invention generally relates to the field of polymercharacterization. In particular, the invention relates to liquidchromatography and related flow-injection analysis techniques forrapidly characterizing polymer solutions, emulsions and dispersions, andto devices for implementing such techniques. In preferred embodiments,the characterization of a polymer sample or of components thereof iseffected with optical detectors. The methods and devices disclosedherein are applicable, inter alia, to the rapid characterization oflibraries of polymers prepared by combinatorial materials sciencetechniques.

Currently, there is substantial research activity directed toward thediscovery and optimization of polymeric materials for a wide range ofapplications. Although the chemistry of many polymers and polymerizationreactions has been extensively studied, it is, nonetheless, rarelypossible to predict a priori the physical or chemical properties aparticular polymeric material will possess or the precise compositionand architecture that will result from any particular synthesis scheme.Thus, characterization techniques to determine such properties are anessential part of the discovery process.

Combinatorial chemistry refers generally to methods for synthesizing acollection of chemically diverse materials and to methods for rapidlytesting or screening this collection of materials for desirableperformance characteristics and properties. Combinatorial chemistryapproaches have greatly improved the efficiency of discovery of usefulmaterials. For example, material scientists have developed and appliedcombinatorial chemistry approaches to discover a variety of novelmaterials, including for example, high temperature superconductors,magnetoresistors, phosphors and catalysts. See, for example, U.S. Pat.No. 5,776,359 to Schultz et al. In comparison to traditional materialsscience research, combinatorial materials research can effectivelyevaluate much larger numbers of diverse compounds in a much shorterperiod of time. Although such high-throughput synthesis and screeningmethodologies are conceptually promising, substantial technicalchallenges exist for application thereof to specific research andcommercial goals.

Methods have been developed for the combinatorial (e.g., rapid-serial orparallel) synthesis and screening of libraries of small molecules ofpharmaceutical interest, and of biological polymers such aspolypeptides, proteins, oligonucleotides and deoxyribonucleic acid (DNA)polymers. However, there have been few reports of the application ofcombinatorial techniques to the field of polymer science for thediscovery of new polymeric materials or polymerization catalysts or newsynthesis or processing conditions. Brocchini et al. describe thepreparation of a polymer library for selecting biomedical implantmaterials. See S. Brocchini et al., A Combinatorial Approach for PolymerDesign, J. Am. Chem. Soc. 119, 4553-4554 (1997). However, Brocchini etal. reported that each synthesized candidate material was individuallyprecipitated, purified, and then characterized according to “routineanalysis” that included gel permeation chromatography to measuremolecular weight and polydispersities. As such, Brocchini et al. did notaddress the need for efficient and rapid characterization of polymers.

Liquid chromatography is well known in the art for characterizing apolymer sample. Liquid chromatographic techniques employ separation ofone or more components of a polymer sample from other components thereofby flow through a chromatographic column, followed by detection of theseparated components with a flow-through detector. Approaches for liquidchromatography can vary, however, with respect to the basis ofseparation and with respect to the basis of detection. Gel permeationchromatography (GPC), a well-known form of size exclusion chromatography(SEC), is a frequently-employed chromatographic technique for polymersize determination. In GPC, the polymer sample is separated intocomponents according to the hydrodynamic volume occupied by eachcomponent in solution. More specifically, a polymer sample is injectedinto a mobile phase of a liquid chromatography system and is passedthrough one or more chromatographic columns packed with porous beads.Molecules with relatively small hydrodynamic volumes diffuse into thepores of the beads and remain therein for longer periods, and thereforeexit the column after molecules with relatively larger hydrodynanicvolume. Hence, GPC can characterize one or more separated components ofthe polymer sample with respect to its effective hydrodynamic radius(R_(h)). Another chromatographic separation approach is illustrated byU.S. Pat. No. 5,334,310 to Frechet et al. and involves the use of aporous monolithic stationary-phase as a separation medium within thechromatographic column, combined with a mobile-phase compositiongradient. (See also, Petro et al, Molded Monolithic Rod of MacroporousPoly(styrene-co-divinylbenzene) as a Separation Medium for HPLCSynthetic Polymers: “On-Column” Precipitation-RedissolutionChromatography as an Alternative to Size Exclusion Chromatography ofStyrene Oligomers and Polymers, Anal. Chem., 68, 315-321 (1996); andPetro et al, Immobilization of Trypsin onto “Molded” Macroporous Poly(Glycidyl Methacrylate-co-Ethylene Dimethacrylate) Rods and Use of theConjugates as Bioreactors and for Affinity Chromatography, Biotechnologyand Bioengineering, Vol. 49, pp. 355-363 (1996)). Chromatographyinvolving the porous monolith is reportedly based on aprecipitation/redissolution phenomenon that separates the polymeraccording to size—with the precipitated polymer molecules selectivelyredissolving as the solvent composition is varied. The monolith providesthe surface area and permeation properties needed for proper separation.Other separation approaches are also known in the art, including forexample, normal-phase adsorption chromatography (with separation ofpolymer components being based on preferential adsorption betweeninteractive functionalities of repeating units and an adsorbingstationary-phase) and reverse-phase chromatography (with separation ofpolymer components being based on hydrophobic interactions between apolymer and a non-polar stationary-phase). After separation, a detectorcan measure a property of the polymer or of a polymer component—fromwhich one or more characterizing properties, such as molecular weightcan be determined as a function of time. Specifically, a number ofmolecular-weight related parameters can be determined, including forexample: the weight-average molecular weight (M_(w)), the number-averagemolecular weight (M_(n)), the molecular-weight distribution shape, andan index of the breadth of the molecular-weight distribution(M_(w)/M_(n)), known as the polydispersity index (PDI). Othercharacterizing properties, such as mass, particle size, composition orconversion can likewise be determined.

Flow-injection analysis techniques have been applied for characterizingsmall molecules, such as pigments. Typically, such techniques includethe detection of a sample with a continuous-flow detector—withoutchromatographic separation prior to detection. However, such approacheshave not, heretofore, been applied in the art of polymercharacterization. Moreover, no effort has been put forth to optimizesuch approaches with respect to sample-throughput.

A variety of continuous-flow detectors have been used for measurementsin liquid chromatography systems. Common flow-through detectors includeoptical detectors such as a differential refractive index detector (RI),an ultraviolet-visible absorbance detector (UV-VIS), or an evaporativemass detector (EMD)—sometimes referred to as an evaporative lightscattering detector (ELSD). Additional detection instruments, such as astatic-light-scattering detector (SLS), a dynamic-light-scatteringdetector (DLS), and/or a capillary-viscometric detector (C/V) arelikewise known for measurement of properties of interest.Light-scattering methods, both static and dynamic, are established inseveral areas of polymer analysis. Static light scattering (SLS) can beused to measure M_(w) and the radii of gyration (R_(g)) of a polymer ina dilute solution of known concentration. Dynamic light scattering (DLS)measures the fluctuations in the scattering signal as a function of timeto determine the diffusion constant of dissolved polymer chains or otherscattering species in dilute solution or of polymer particles comprisingmany chains in a heterogeneous system such as dilute emulsion or latexdispersion. The hydrodynamic radius, R_(h), of the chains or particlescan then be calculated based on well-established models.

Presently known liquid chromatography systems and flow-injectionanalysis systems are not suitable for efficiently screening largernumbers of polymer samples. Known chromatographic techniques cantypically take up to an hour for each sample to ensure a high degree ofseparation over the wide range of possible molecular weights (i.e.,hydrodynamic volumes) for a sample. The known chromatographic techniquescan be even longer if the sample is difficult to dissolve or if otherproblems arise. Additionally, polymer samples are typically prepared forcharacterization manually and individually, and some characterizationsystems require specially-designed sample containers and/or substantialdelay-times. For example, optical methods such as light-scatteringprotocols typically employ detector-specific cuvettes which are manuallyplaced in a proper location in the light-scattering instrument. Suchoptical protocols can also require a sample to thermally equilibrate forseveral minutes before measurement. Moreover, because of the nature ofmany commercial polymers and/or polymer samples—such as theirnon-polarity and insolubility in water and/or alcohols, theirheterogeneous nature, their lack of sequence specificity, among otheraspects, the methods, systems and devices developed in connection withthe biotechnological, pharmaceutical and clinical-diagnostic arts aregenerally not instructive for characterizing polymers. Hence, knownapproaches are not well suited to the rapid characterization ofpolymers.

Aspects of polymer characterization, such as sample preparation andpolymer separation, have been individually and separately investigated.For example, Poché et al. report a system and approach for automatedhigh-temperature dissolution of polymer samples. See Poché et al., Useof Laboratory Robotics for Gel Permeation Chromatography SamplePreparation: Automation of High-Temperature Polymer Dissolution, J.Appl. Polym. Sci., 64(8), 1613-1623 (1997). Stationary-phase media thatreduce chromatographic separation times of individual polymer sampleshave also been reported. See, for example, Petro et al., Moldedcontinuous poly(styrene-co-divinylbenzene) rod as a separation mediumfor the very fast separation of polymers; Comparison of thechromatographic properties of the monolithic rod with columns packedwith porous and no-porous beads in high-performance liquidchromatography., Journal of Chromatography A, 752, 59-66 (1996); andPetro et al., Monodisperse Hydrolyzed Poly(glycidylmethacrylate-co-ethylene dimethacrylate) Beads as a Stationary Phase forNormal-Phase HPLC, Anal. Chem., 69, 3131 (1997). However, suchapproaches have not contemplated nor been incorporated into protocolsand systems suitable for large-scale, or even moderate-scale,combinatorial chemistry research, and particularly, for combinatorialmaterial science research directed to the characterization of polymers.

With the development of combinatorial techniques that allow for theparallel synthesis of arrays comprising a vast number of diverseindustrially relevant polymeric materials, there is a need for methodsand devices and systems to rapidly characterize the properties of thepolymer samples that are synthesized.

SUMMARY OF INVENTION

It is therefore an object of the present invention to provide systemsand protocols for characterizing combinatorial libraries of polymersamples, and particularly, libraries of or derived from polymerizationproduct mixtures, to facilitate the discovery of commercially importantpolymeric materials, catalysts, polymerization conditions and/orpost-synthesis processing conditions. It is also an object of theinvention to provide polymer characterization systems and protocols thatcan be employed in near-real-time industrial process control.

Briefly, therefore, this invention provides methods and apparatus forthe rapid characterization or screening of polymers by chromatographictechniques and related flow-injection analysis techniques, andparticularly, those employing optical detection methods. This inventionprovides a number of embodiments for such rapid characterization orscreening of polymers and those embodiments can be employed individuallyor combined together. More specifically, polymer characterizationapproaches and devices are presented involving flow characterization andnon-flow characterization, and with respect to both of the same,involving rapid-serial, parallel, serial-parallel and hybridparallel-serial approaches. Some preferred approaches and embodimentsare directed to rapid-serial flow characterization of polymer samples.

Among the several significant aspects of the rapid-serial flowcharacterization techniques are protocols and systems related toautomated sampling, chromatographic separation (where applicable) and/ordetection—which individually and collectively improve thesample-throughput when applied to characterize a plurality of polymersamples. The automated polymer sampling can be effected at fastersampling rates, with equipment optimized for such purposes, and insequences that benefit overall throughput and/or minimize extraneoussteps. A number of chromatographic separation techniques can be employedto efficiently and effectively separate one or more of the variouscomponents of a heterogeneous polymer sample from one or more othercomponents thereof. Generally, such techniques relate to columngeometry, separation medium and mobile-phase medium. Certain approachesand systems disclosed herein involve improved aspects of detection. Inaddition, rapid, indirect calibration standards and methods impactoverall system speed. Moreover, several important aspects of theinvention have direct implications for high-temperature characterizationefforts (typically ranging from about 75° C. to about 225° C.).

Many of such aspects of the invention can be directly translated for usewith parallel or serial-parallel protocols, in addition to rapid-serialprotocols. In a preferred embodiment, for example, a parallel orserial-parallel dynamic light-scattering system and protocols can beused for polymer characterization with very high sample throughput.

Hence the methods, systems and devices of the present invention areparticularly suited for screening of arrays of polymerization productmixtures prepared in the course of combinatorial materialsdiscovery—thereby providing a means for effectively and efficientlycharacterizing large numbers of different polymeric materials. Whilesuch methods, systems and devices have commercial application incombinatorial materials science research programs, they can likewise beapplied in industrial process applications for near-real-time processmonitoring or process control.

Other features, objects and advantages of the present invention will bein part apparent to those skilled in art and in part pointed outhereinafter. All references cited in the instant specification areincorporated by reference for all purposes. Moreover, as the patent andnon-patent literature relating to the subject matter disclosed and/orclaimed herein is substantial, many relevant references are available toa skilled artisan that will provide further instruction with respect tosuch subject matter.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1A through FIG. 1F are schematic diagrams showing an overview ofpolymer characterization process steps (FIG. 1A), a rapid-serialprotocol for effecting such steps (FIG. 1B) for a plurality of samples(s₁, s₂, s₃ . . . s_(n)) to obtain corresponding characterizing propertyinformation (p₁, p₂, p₃ . . . p_(n)), a parallel protocol for effectingsuch steps (FIG. 1C) and several parallel-serial hybrid protocols foreffecting such steps (FIG. 1D, FIG. 1E, FIG. 1F).

FIG. 2A and FIG. 2B are schematic diagrams illustrating liquidchromatography (FIG. 2A) and flow-injection analysis (FIG. 2B) flowcharacterization systems.

FIG. 3 is a schematic diagram illustrating an eight-port injection valveused for loading a polymer sample and for injection thereof into amobile phase of a flow characterization system.

FIG. 4 is a schematic diagram illustrating an automated sampling system.

FIG. 5A through FIG. 5C are views of several embodiments of atemperature-controlled auto-sampler injection probe. FIGS. 5A and 5B arecross-sectional side views of an auto-sampler probe having a resistivetemperature-control element (FIG. 5A) and a fluid heat-exchanger typetemperature-control element (FIG. 5B), respectively. FIG. 5C is aperspective view of an auto-sampler probe having a body with a largethermal mass.

FIG. 6 is a schematic diagram illustrating a preferred embodiment of aliquid chromatography system having high-temperature characterizationcapabilities.

FIG. 7A through FIG. 7D relate to preferred liquid chromatography andflow-injection analysis systems and/or operational aspects thereof.FIGS. 7A and 7B are schematic diagrams illustrating preferredembodiments of flow characterization systems capable of use for liquidchromatography or flow-injection analysis and having a singlemicroprocessor control (FIG. 7A) or multi-microprocessor control (FIG.7B). FIG. 7C is a schematic diagram illustrating a preferred embodimentfor a flow-injection analysis system, referred to as a flow-injectionlight-scattering (FILS) system. FIG. 7D is a schematic diagramillustrating one approach for effecting control of the mobile-phaseflowrate in a variable-flow light-scattering system.

FIG. 8 is a graph of detector output (mv) versus time (minutes)illustrating the results from a gel permeation/adsorption HPLCseparation of a typical emulsion sample diluted by THF from Example 10.The upper trace is from a refractive index (RI) detector. The lower twotraces are from a static light-scattering detector (SLS) at 90° (middletrace) and at 15° (lower trace).

FIG. 9 is a graph of retentate amount (%) versus time (minutes)illustrating refractive index traces for latex particles of differentsizes (204 nm, 50 nm, 19 nm) from Example 11 following chromatographicseparation (main traces), and without chromatographic separation(superimposed traces in lower-left-hand corner).

FIG. 10 is a graph of detector response (mv) versus time (minutes)illustrating light-scattering traces (LS 90°—upper set of traces) andrefractive index traces (RI—lower set of traces) for latex particles ofdifferent sizes (204 nm, 50 nm, 19 nm) under the same flow conditionsfrom Example 12.

FIGS. 11A and 11B are graphs showing the results of Example 15. FIG. 11Ais a graph of detector response (au) versus time (minutes)—showingoverlaid chromatographs from a set of polymer standards. FIG. 11B is acalibration curve corresponding to the traces of FIG. 11A.

FIGS. 12A through FIG. 12C are graphs showing the results of Example 16.FIG. 12A is a graph of detector response (mv) versus retention time(minutes) and includes traces for each of a plurality ofserially-characterized samples—with the traces being electronicallyoverlaid on a single chromatograph. FIG. 12B is a graph of detectorresponse (mv) versus retention time (minutes) for a “single-shot”indirect calibration standard for the samples being characterized. FIG.12C is a graph of log molecular weight versus retention time (minutes)and is the calibration curve corresponding to FIG. 12B.

FIG. 13 is a graph of detector response (mv) versus retention time(minutes) as a chromatograph for a representative sample characterizedin Example 17.

FIGS. 14A and 14B are three-dimensional bar-graphs showing thedetermined weight-average molecular weight for each of the samples of alibrary of samples (identified by location in a 96-well microtiter-typesample-container having 8 rows and 12 columns) as characterized usingaccelerated SEC (FIG. 14A) and rapid SEC (FIG. 14B) approaches detailedin Example 18A.

FIGS. 15A through 15F are graphs showing data from Example 18B. FIGS.15A through 15C show the determined weight-average molecular weight(FIG. 15A), the determined polydispersity index (FIG. 15B) and thedetermined conversion (FIG. 15C) for each of the library samples(identified by location in a 96-well microtiter-type sample-containerhaving 8 rows and 12 columns) as characterized using an accelerated SECapproach. FIGS. 15D through 15F show the determined weight-averagemolecular weight (FIG. 15D), the determined polydispersity index (FIG.15E) and the determined conversion (FIG. 15F) for each of the librarysamples as characterized using an enhanced rapid SEC approach. For eachgraph, values for the determined properties are represented by relativesize of the circle indicated for that sample. The absence of a circlefor a particular sample indicates that the property was not determinedfor that particular sample.

FIGS. 16A and 16B are graphs of detector response (mv) versus retentiontime (minutes) for a polymer sample characterized in two differentliquid chromatography systems illustrated in Example 19. The systemswere identical except with respect to the detector—one system employinga RI detector (FIG. 16A) and the other system employing an ELSD detector(FIG. 16B).

FIGS. 17A and 17B are three-dimensional bar graphs showing thedetermined conversion (FIG. 17A) and the determined weight-averagemolecular weight (FIG. 17B) for the polystyrene samples (columns 1-4),the polymethylmethacrylate samples (columns 4-6), the polybutylacrylatesamples (columns 7-9) and the polyvinylacetate samples (columns 10-12)characterized with SEC-adsorption chromatography approaches illustratedin Example 20.

FIGS. 18A and 18B show the results of high-temperature characterizationexperiments of Example 21A. FIG. 18A is a graph of detector response(mv) versus retention time (minutes) for serially characterizedpolystyrene standards overlaid as a single trace. FIG. 18B is a graph oflog molecular weight versus retention time as a calibration curve forrepresentative polyethylene standards.

FIGS. 19A and 19B show the results of high-temperature characterizationexperiments of Example 21B. FIG. 19A is a graph of detector response(mv) versus retention time (minutes) for serially characterizedrepresentative polystyrene standards and polyethylene standards overlaidas a single trace. FIG. 19B is a graph of log molecular weight versusretention time as a calibration curve for representative polyethylenestandards.

FIG. 20 is a graph of detector response (mv) versus retention time(minutes) with superimposed traces for a polyethylene (PE) polymersample characterized by liquid chromatography approach illustrated inExample 22. Elution of the PE sample was effectively controlled bycontrolling the temperature of the mobile phase—in a first experiment ascontinuously “hot trichlorobenzene (TCB)” and in a second experiment as“cold TCB” for about 2 minutes and then “hot TCB” for the remainder ofthe run.

FIGS. 21A and 21B are graphs of detector response (mv) versus retentiontime (minutes) and show the resulting chromatographs for thecharacterization of 96 polymer samples using the SLS detector (FIG. 21A)and the ELSD (FIG. 21B) in the very rapid flow-injectionlight-scattering approach illustrated in Example 23.

FIGS. 22A and 22B are graphs of detector response (mv) versus retentiontime (minutes) and are chromatographs for single-shot calibration usingeight pooled, commercially-available polyisobutylene (PIB) standards(FIG. 22A), and for eight pooled, particularly-selected polystyrenestandards having hydrodynamic volumes that are substantially the same asthe hydrodynamic volumes for the PIB standards (FIG. 22B), as determinedin Example 25.

FIGS. 23A and 23B are graphs of log molecular weight versus retentiontime (minutes) developed in connection with Example 25. FIG. 23A is anabsolute (direct) polyisobutylene (PIB) calibration curve prepared froma set of nine commercially-available PIB standards that wereindividually and serially determined in nine separate characterizationruns. FIG. 23B is an indirect PIB calibration curve prepared from a setof nine polystyrene (PS) standards preselected based on hydrodynamicvolume to correspond with certain PIB standards, and pooled to form aset of polystyrene standards (the small molecular weight standard beingomitted), that were, effectively, a composition suitable for single-shotindirect calibration for polyisobutylene.

FIG. 24 is a schematic diagram illustrating a parallel, non-flow,non-immersion dynamic light-scattering (DLS) polymer characterizationsystem.

The invention is described in further detail below with reference to thefigures, in which like items are numbered the same in the severalfigures.

DETAILED DESCRIPTION OF THE INVENTION

In the present invention, methods and apparatus having features thatenable an effective combinatorial polymer research program are provided.Such a research program may be directed, for example, to identifying oroptimizing commercially valuable polymers, catalysts or other materials,or to other research goals, such as process characterization andoptimization. Other applications, including industrial processmonitoring or control are also enabled by the present invention.

More specifically, polymer characterization approaches and devices arepresented involving flow characterization and non-flow characterization,and with respect to both of the same, involving rapid-serial, parallel,serial-parallel and hybrid parallel-serial approaches. Some preferredapproaches and embodiments are directed to rapid-serial flowcharacterization of polymer samples. Among the several significantaspects of the rapid-serial flow characterization techniques areprotocols and systems related to automated sampling, chromatographicseparation (where applicable) and/or detection—which individually andcollectively improve the sample-throughput when applied to characterizea plurality of polymer samples.

With respect to automated polymer sampling, for example, a plurality ofpolymer samples can be loaded into a flow characterization system usingan auto-sampler having a very high sampling rate—less than 10 secondsper sample, or in some embodiments, less than 5 seconds per sample.Additionally, automated sample preparation can be effected in a directrapid-serial manner (i.e., serial samplewithdrawal-preparation-loading). The plurality of samples can be loaded,moreover, into an injection valve having two sample-loops—therebyproviding a load-load capability wherein a second sample can be loadedwhile the first sample is being injected into the characterizationsystem.

With respect to chromatographic separation, a number of techniques canbe employed to efficiently and effectively separate one or more of thevarious components of a heterogeneous polymer sample from one or moreother components thereof. For example, the column geometry, preferablyin combination with the separation medium, can be optimized to obtainthe desired throughput. Preferred column geometries include relativelyshort, high-aspect ratio columns (as compared to conventional columns).Preferred separation media include a stationary phase selected fortargeted separation ranges—for example, to quickly pass a highmolecular-weight fraction of a sample (e.g., > about 1000 D) whileretaining a low molecular-weight fraction of the sample. Otherseparation medium optimization approaches, such as combiningsize-exclusion chromatography (SEC) with an adsorption chromatography,are also preferred in some applications. The mobile phase of a liquidchromatography system can also be controlled to improvesample-throughput. For example, mobile-phase compositional gradients,mobile-phase temperature gradients or mobile-phase flowrate gradientscan be employed individually or collectively, and the time-rate ofchange of such gradients can affect separation performance. For someapplications, solvent selection can itself be optimized to improve theefficiency of loading and/or eluting the sample or components thereofonto/from the stationary phase.

For flow characterization systems generally (including both liquidchromatography systems and flow-injection analysis systems), theflow-rate of the mobile phase can be increased substantially (e.g., by afactor of ten or more) relative to conventional flow characterizationsystems. The mobile phase flow rates can also be temporally varied as asample moves through a flow characterization system—for example, withrelatively high flowrates to advance the sample to a detector, andrelatively slow flowrates to detect a property of the sample or of acomponent thereof.

With respect to detection, a low-molecular weight insensitive massdetector, such as an evaporative light-scattering detector (ELSD) can beadvantageously employed in liquid chromatography approaches incooperation with overlaid sample injection approaches. Specifically,trailing-edge components from a preceding sample and leading-edgecomponents from a succeeding sample can reside in a detection cavitysimultaneously, without compromising relevant data collection. Inaddition, rapid, indirect calibration standards and methods impactoverall system speed.

Several important aspects of the invention have direct implications forhigh-temperature characterization efforts (typically ranging from about75° C. to about 225° C.). With regard to polymer sampling, for example,a directly heated auto-sampler probe is employed. Chromatographiccolumns of relatively small mass (as compared to conventional columns)allow for rapid thermal equilibrilization of the system. With respect tochromatographic separation, mobile-phase temperature and compositiongradients can be employed. Finally, detectors that are less-sensitive tovariations in temperature, as compared with typical high-temperaturecharacterization detectors, offer a greater degree of freedom for systemconfiguration at reduced costs.

Many of such aspects of the invention can be directly translated for usewith parallel or serial-parallel protocols, in addition to rapid-serialprotocols. In a preferred embodiment, for example, a parallel orserial-parallel dynamic light-scattering system and protocols can beused for polymer characterization with very high sample throughput.

These and other aspects of the invention are to be considered exemplaryand non-limiting, and are discussed in greater detail below. The severalaspects of the polymer characterization methods and systems disclosedand claimed herein can be advantageously employed separately, or incombination to efficiently characterize polymeric materials. Inpreferred embodiments, these features are employed in combination toform a polymer characterization system that can operate as ahigh-throughput screen in a materials science research program directedto identifying and optimizing new polymers, new catalysts, newpolymerization reaction conditions and/or new post-synthesis processingconditions. Certain characterizing information—particularly molecularweight, molecular weight distribution, composition and conversioninformation—are broadly useful for characterizing polymers andpolymerization reactions. As such, the particular polymers and/ormechanisms disclosed herein should be considered exemplary of theinvention and non-limiting as to the scope of the invention.

Combinatorial Approaches for Polymer Science Research

In a combinatorial approach for identifying or optimizing polymericmaterials or polymerization reaction conditions, a large compositionalspace (e.g., of monomers, comonomers, catalysts, catalyst precursors,solvents, initiators, additives, or of relative ratios of two or more ofthe aforementioned) and/or a large reaction condition space (e.g., oftemperature, pressure and reaction time) may be rapidly explored bypreparing polymer libraries and then rapidly screening such libraries.The polymer libraries can comprise, for example, polymerization productmixtures resulting from polymerization reactions that are varied withrespect to such factors.

Combinatorial approaches for screening a polymer library can include aninitial, primary screening, in which polymerization product mixtures arerapidly evaluated to provide valuable preliminary data and, optimally,to identify several “hits”—particular candidate materials havingcharacteristics that meet or exceed certain predetermined metrics (e.g.,performance characteristics, desirable properties, unexpected and/orunusual properties, etc.). Such metrics may be defined, for example, bythe characteristics of a known or standard polymer or polymerizationscheme. Because local performance maxima may exist in compositionalspaces between those evaluated in the primary screening of the firstlibraries or alternatively, in process-condition spaces different fromthose considered in the first screening, it may be advantageous toscreen more focused polymer libraries (e.g., libraries focused on asmaller range of compositional gradients, or libraries comprisingcompounds having incrementally smaller structural variations relative tothose of the identified hits) and additionally or alternatively, subjectthe initial hits to variations in process conditions. Hence, a primaryscreen can be used reiteratively to explore localized and/or optimizedcompositional space in greater detail. The preparation and evaluation ofmore focused polymer libraries can continue as long as thehigh-throughput primary screen can meaningfully distinguish betweenneighboring library compositions or compounds.

Once one or more hits have been satisfactorily identified based on theprimary screening, polymer and polymerization product libraries focusedaround the primary-screen hits can be evaluated with a secondaryscreen—a screen designed to provide (and typically verified, based onknown materials, to provide) chemical process conditions that relatewith a greater degree of confidence to commercially-important processesand conditions than those applied in the primary screen. In manysituations, such improved “real-world-modeling” considerations areincorporated into the secondary screen at the expense of methodologyspeed (e.g., as measured by sample throughput) compared to acorresponding primary screen. Particular polymer materials, catalysts,reactants, polymerization conditions or post-synthesis processingconditions having characteristics that surpass the predetermined metricsfor the secondary screen may then be considered to be “leads.” Ifdesired, additional polymer or polymerization product libraries focusedabout such lead materials can be screened with additional secondaryscreens or with tertiary screens. Identified lead polymers, monomers,catalysts, catalyst precursors, initiators, additives or reactionconditions may be subsequently developed for commercial applicationsthrough traditional bench-scale and/or pilot scale experiments.

While the concept of primary screens and secondary screens as outlinedabove provides a valuable combinatorial research model for investigatingpolymers and polymerization reactions, a secondary screen may not benecessary for certain chemical processes where primary screens providean adequate level of confidence as to scalability and/or where marketconditions warrant a direct development approach. Similarly, whereoptimization of materials having known properties of interest isdesired, it may be appropriate to start with a secondary screen. Ingeneral, the systems, devices and methods of the present invention maybe applied as either a primary or a secondary screen, depending on thespecific research program and goals thereof. See, generally, U.S. patentapplication Ser. No. 09/227,558 entitled “Apparatus and Method ofResearch for Creating and Testing Novel Catalysts, Reactions andPolymers”, filed Jan. 8, 1999 by Turner et al., for further discussionof a combinatorial approach to polymer science research.

Polymer Characterization—General Approaches

According to the present invention, methods, systems and devices aredisclosed that improve the efficiency and/or effectiveness of the stepsnecessary to characterize a polymer sample or a plurality of polymersamples (e.g., libraries of polymerization product mixtures). Inpreferred embodiments, a property of a plurality of polymer samples orof components thereof can be detected in a polymer characterizationsystem with an average sample-throughput sufficient for an effectivecombinatorial polymer science research program.

With reference to FIG. 1A, characterizing a polymer sample can include(A) preparing the sample (e.g., dilution), (B) injecting the sample intoa mobile phase of a flow characterization system (e.g., liquidchromatography system, flow-injection analysis system), (C) separatingthe sample chromatographically, (D) detecting a property of the polymersample or of a component thereof, and/or (E) correlating the detectedproperty to a characterizing property of interest. As depicted in FIG.1A, various characterization protocols may be employed involving some orall of the aforementioned steps. For example, a property of a polymersample may be detected in a non-flow, static system either withpreparation (steps A and D) or without preparation (step D).Alternatively, a property of a polymer sample may be detected in a flowcharacterization system—either with or without sample preparation andeither with or without chromatographic separation. In characterizationprotocols involving flow characterization systems withoutchromatographic separation (referred to herein as flow-injectionanalysis systems) a property of a polymer sample may be detected in aflow-injection analysis system either with preparation (steps A, B andD) or without preparation (steps B and D). If chromatographic separationof a polymer sample is desired, a property of the sample may be detectedin a liquid chromatography system either with preparation (steps A, B, Cand D) or without preparation (steps B, C and D). While thephysically-detected property (e.g., refracted light, absorbed light,scattered light) from two samples being screened could be compareddirectly, in most cases the detected property is preferably correlatedto a characterizing property of interest (e.g., molecular weight) (stepE).

A plurality of polymer samples may be characterized as described abovein connection with FIG. 1A. As a general approach for improving thesample throughput for a plurality of polymers, each of the steps, (A)through (E) of FIG. 1A applicable to a given characterization protocolcan be optimized with respect to time and quality of information, bothindividually and in combination with each other. Additionally oralternatively, each or some of such steps can be effected in arapid-serial, parallel, serial-parallel or hybrid parallel-serialmanner.

The throughput of a plurality of samples through a single step in acharacterization process is improved by optimizing the speed of thatstep, while maintaining—to the extent necessary—the information-qualityaspects of that step. In many cases, such as with chromatographicseparation, speed can be gained at the expense of resolution of theseparated components. Although conventional research norms, developed inthe context in which research was rate-limited primarily by thesynthesis of polymer samples, may find such an approach less than whollysatisfactory, the degree of rigor can be entirely satisfactory for aprimary or a secondary screen of a combinatorial library of polymersamples. For combinatorial polymer research (and as well, for manyon-line process control systems), the quality of information should besufficiently rigorous to provide for scientifically acceptabledistinctions between the compounds or process conditions beinginvestigated, and for a secondary screen, to provide for scientificallyacceptable correlation (e.g., values or, for some cases, trends) withmore rigorous, albeit more laborious and time-consuming traditionalcharacterization approaches.

The throughput of a plurality of samples through a series of steps,where such steps are repeated for the plurality of samples, can also beoptimized. In one approach, one or more steps of the cycle can becompressed relative to traditional approaches or can have leading orlagging aspects truncated to allow other steps of the same cycle tooccur sooner compared to the cycle with traditional approaches. Inanother approach, the earlier steps of a second cycle can be performedconcurrently with the later steps of a first cycle. For example, withreference to FIG. 1A in a rapid-serial approach for characterizing asample, sample preparation for a second sample in a series can beeffected while the first sample in the series is being separated and/ordetected. As another example, a second sample in a series can beinjected while the first sample in the series is being separated and/ordetected. These approaches, as well as others, are discussed in greaterdetail below.

A characterization protocol for a plurality of samples can involve asingle-step process (e.g., direct, non-flow detection of a property of apolymer sample or of a component thereof, depicted as step D of FIG.1A). In a rapid-serial detection approach for a single-step process, theplurality of polymer samples and a single detector are seriallypositioned in relation to each other for serial detection of thesamples. In a parallel detection approach, two or more detectors areemployed to detect a property of two or more samples simultaneously. Ina direct, non-flow detection protocol, for example, two or more samplesand two or more detectors can be positioned in relation to each other todetect a property of the two or more polymer samples simultaneously. Ina serial-parallel detection approach, a property of a larger number ofpolymer samples (e.g., four or more) is detected as follows. First, aproperty of a subset of the four or more polymer samples (e.g., 2samples) is detected in parallel for the subset of samples, and thenserially thereafter, a property of another subset of four or moresamples is detected in parallel.

For characterization protocols involving more than one step (e.g., stepsA, D and E; steps B, D and E; steps A, B, D and E; steps B, C, D and E;or steps A, B, C, D and E of FIG. 1A), optimization approaches to effecthigh-throughput polymer characterization can vary. As one example,represented schematically in FIG. 1B, a plurality of polymer samples canbe characterized with a single polymer characterization system (I) in arapid-serial approach in which each of the plurality of polymer samples(s₁, s₂, s₃ . . . s_(n)) are processed serially through thecharacterization system (I) with each of the steps (A, B, C, D, E)effected in series on each of the of samples to produce a serial streamof corresponding characterizing property information (p₁, p₂, p₃ . . .p_(n)). This approach benefits from minimal capital investment, and mayprovide sufficient throughput—particularly when the steps (A) through(E) have been optimized with respect to speed and quality ofinformation. As another example, represented schematically in FIG. 1C, aplurality of polymer samples can be characterized with two or morepolymer characterization systems (I, II, III . . . N) in a pure parallel(or for larger libraries, serial-parallel) approach in which theplurality of polymer samples (s₁, s₂, s₃ . . . s_(n)) or a subsetthereof are processed through the two or more polymer characterizationsystems (I, II, III . . . N) in parallel, with each individual systemeffecting each step on one of the samples to produce the characterizingproperty information (p₁, p₂, p₃ . . . p_(n)) in parallel. This approachis advantageous with respect to overall throughput, but may beconstrained by the required capital investment.

In a hybrid approach, certain of the steps of the characterizationprocess can be effected in parallel, while certain other steps can beeffected in series. Preferably, for example, it may be desirable toeffect the longer, throughput-limiting steps in parallel for theplurality of samples, while effecting the faster, less limiting steps inseries. Such a parallel-series hybrid approach can be exemplified, withreference to FIG. 1D, by parallel sample preparation (step A) of aplurality of polymer samples (s₁, s₂, s₃ . . . s_(n)), followed byserial injection, chromatographic separation, detection and correlation(steps B, C, D and E) with a single characterization system (I) toproduce a serial stream of corresponding characterizing propertyinformation (p₁, p₂, p₃ . . . p_(n)). In another exemplaryparallel-series hybrid approach, represented schematically in FIG. 1E, aplurality of polymer samples (s₁, s₂, s₃ . . . s_(n)) are prepared andinjected in series into the mobile phase of four or more liquidchromatography characterizing systems (I, II, III . . . N), and thenseparated, detected and correlated in a slightly offset (staggered)parallel manner to produce the characterizing property information (p₁,p₂, p₃ . . . p_(n)) in the same staggered-parallel manner. If each ofthe separation and detection systems has the same processing rates, thenthe extent of the parallel offset (or staggering) will be primarilydetermined by the speed of the serial preparation and injection. In avariation of the preceding example, with reference to FIG. 1F, where thedetection and correlation steps are sufficient fast, a plurality ofpolymer samples (s₁, s₂, s₃ . . . s_(n)) could be characterized byserial sample preparation and injection, staggered-parallelchromatographic separation, and then serial detection and correlation,to produce the characterizing property information (p₁, p₂, p₃ . . .p_(n)) in series. In this case, the rate of injection into the variousseparation columns is preferably synchronized with the rate ofdetection.

Optimization of individual characterization steps (e.g., steps (A)through (E) of FIG. 1A) with respect to speed and quality of informationcan improve sample throughput regardless of whether the overallcharacterization scheme involves a rapid-serial or parallel aspect(i.e., true parallel, serial-parallel or hybrid parallel-seriesapproaches). As such, the optimization techniques disclosed hereinafter,while discussed primarily in the context of a rapid-serial approach, arenot limited to such an approach, and will have application to schemesinvolving parallel characterization protocols.

Polymer Samples

The polymer sample can be a homogeneous polymer sample or aheterogeneous polymer sample, and in either case, comprises one or morepolymer components. As used herein, the term “polymer component” refersto a sample component that includes one or more polymer molecules. Thepolymer molecules in a particular polymer component have the same repeatunit, and can be structurally identical to each other or structurallydifferent from each other. For example, a polymer component may comprisea number of different molecules, with each molecule having the samerepeat unit, but with a number of molecules having different molecularweights from each other (e.g., due to a different degree ofpolymerization). As another example, a heterogeneous mixture ofcopolymer molecules may, in some cases, be included within a singlepolymer component (e.g., a copolymer with a regularly-occurring repeatunit), or may, in other cases, define two or more different polymercomponents (e.g., a copolymer with irregularly-occurring orrandomly-occurring repeat units). Hence, different polymer componentsinclude polymer molecules having different repeat units. It is possiblethat a particular polymer sample (e.g., a member of a library) will notcontain a particular polymer molecule or polymer component of interest.

The polymer molecule of the polymer component is preferably anon-biological polymer. A non-biological polymer is, for purposesherein, a polymer other than an amino-acid polymer (e.g., protein) or anucleic acid polymer (e.g., deoxyribonucleic acid (DNA)). Thenon-biological polymer molecule of the polymer component is, however,not generally critical; that is, the systems and methods disclosedherein will have broad application with respect to the type (e.g.,architecture, composition, synthesis method or mechanism) and/or nature(e.g., physical state, form, attributes) of the non-biological polymer.Hence, the polymer molecule can be, with respect to homopolymer orcopolymer architecture, a linear polymer, a branched polymer (e.g.,short-chain branched, long-chained branched, hyper-branched), across-linked polymer, a cyclic polymer or a dendritic polymer. Acopolymer molecule can be a random copolymer molecule, a block copolymermolecule (e.g., di-block, tri-block, multi-block, taper-block), a graftcopolymer molecule or a comb copolymer molecule. The particularcomposition of the non-biological polymer molecule is not critical, andcan include repeat units or random occurrences of one or more of thefollowing, without limitation: polyethylene, polypropylene, polystyrene,polyolefin, polyimide, polyisobutylene, polyacrylonitrile, poly(vinylchloride), poly(methyl methacrylate), poly(vinyl acetate),poly(vinylidene chloride), polytetrafluoroethylene, polyisoprene,polyacrylamide, polyacrylic acid, polyacrylate, poly(ethylene oxide),poly(ethyleneimine), polyamide, polyester, polyurethane, polysiloxane,polyether, polyphosphazine, polymethacrylate, and polyacetals.Polysaccharides are also preferably included within the scope ofnon-biological polymers. While some polysaccharides are of biologicalsignificance, many polysaccharides, and particularly semi-syntheticpolysaccharides have substantial industrial utility with little, if anybiological significance. Exemplary naturally-occurring polysaccharidesinclude cellulose, dextran, gums (e.g., guar gum, locust bean gum,tamarind xyloglucan, pullulan), and other naturally-occurring biomass.Exemplary semi-synthetic polysaccharides having industrial applicationsinclude cellulose diacetate, cellulose triacetate, acylated cellulose,carboxymethyl cellulose and hydroxypropyl cellulose. In any case, suchnaturally-occurring and semi-synthetic polysaccharides can be modifiedby reactions such as hydrolysis, esterification, alkylation, or by otherreactions.

In typical applications, a polymer sample is a heterogeneous samplecomprising one or more polymer components, one or more monomercomponents and/or a continuous fluid phase. In copolymer applications,the polymer sample can comprise one or more copolymers, a firstcomonomer, a second comonomer, additional comonomers, and/or acontinuous fluid phase. The polymer samples can, in any case, alsoinclude other components, such as catalysts, catalyst precursors (e.g.,ligands, metal-precursors), solvents, initiators, additives, products ofundesired side-reactions (e.g., polymer gel, or undesired homopolymer orcopolymers) and/or impurities. Typical additives include, for example,surfactants, control agents, plasticizers, cosolvents and/oraccelerators, among others. The various components of the heterogeneouspolymer sample can be uniformly or non-uniformly dispersed in thecontinuous fluid phase.

The polymer sample is preferably a liquid polymer sample, such as apolymer solution, a polymer emulsion, a polymer dispersion or a polymerthat is liquid in the pure state (i.e., a neat polymer). A polymersolution comprises one or more polymer components dissolved in asolvent. The polymer solution can be of a form that includeswell-dissolved chains and/or dissolved aggregated micelles. The solventcan vary, depending on the application, for example with respect topolarity, volatility, stability, and/or inertness or reactivity. Typicalsolvents include, for example, tetrahydrofuran (THF), toluene, hexane,ethers, trichlorobenzene, dichlorobenzene, dimethylformamide, water,aqueous buffers, alcohols, etc. According to traditional chemistryconventions, a polymer emulsion can be considered to comprise one ormore liquid-phase polymer components emulsified (uniformly ornon-uniformly) in a liquid continuous phase, and a polymer dispersioncan be considered to comprise solid particles of one or more polymercomponents dispersed (uniformly or non-uniformly) in a liquid continuousphase. The polymer emulsion and the polymer dispersion can also beconsidered, however, to have the more typically employed meaningsspecific to the art of polymer science—of being aemulsion-polymerization product and dispersion-polymerization product,respectively. In such cases, for example, the emulsion polymer samplecan more generally include one or more polymer components that areinsoluble, but uniformly dispersed, in a continuous phase, with typicalemulsions including polymer component particles ranging in diameter fromabout 2 nm to about 500 nm, more typically from about 20 nm to about 400nm, and even more typically from about 40 nm to about 200 nm. Thedispersion polymer sample can, in such cases, generally include polymercomponent particles that are dispersed (uniformly or nonuniformly) in acontinuous phase, with typical particles having a diameter ranging fromabout 0.2 μm to about 1000 μm, more typically from about 0.4 μm to about500 μm, and even more typically from about 0.5 μm to about 200 μm.Exemplary polymers that can be in the form of neat polymer samplesinclude dendrimers, and siloxane, among others. The liquid polymersample can also be employed in the form of a slurry, a latex, a microgela physical gel, or in any other form sufficiently tractable for analysisas described and claimed herein. Liquid samples are useful in theautomated sample-handling tools that prepare and automatically sampleeach member of a polymer library. Liquid samples also allow the sampleto flow in the chromatographic system or characterization system. Insome cases, polymer synthesis reactions (i.e., polymerizations) directlyproduce liquid samples. These may be bulk liquid polymers, polymersolutions, or heterogeneous liquid samples such as polymer emulsions,latices, or dispersions. In other cases, the polymer may be synthesized,stored or otherwise available for characterization in a non-liquidphysical state, such as a solid state (e.g., crystalline,semicrystalline or amorphous), a glassy state or rubbery state. Hence,the polymer sample may need to be dissolved, dispersed or emulsified toform a liquid sample by addition of a continuous liquid-phase such as asolvent. The polymer sample can, regardless of its particular form, havevarious attributes, including variations with respect to polarity,solubility and/or miscibility.

In preferred applications, the polymer sample is a polymerizationproduct mixture. As used herein, the term “polymerization productmixture” refers to a mixture of sample components obtained as a productfrom a polymerization reaction. An exemplary polymerization productmixture can be a sample from a combinatorial library prepared bypolymerization reactions, or can be a polymer sample drawn off of anindustrial process line. In general, the polymer sample may be obtainedafter the synthesis reaction is stopped or completed or during thecourse of the polymerization reaction. Alternatively, samples of eachpolymerization reaction can be taken and placed into an intermediatearray of vessels at various times during the course of the synthesis,optionally with addition of more solvent or other reagents to arrest thesynthesis reaction or prepare the samples for analysis. Theseintermediate arrays can then be characterized at any time withoutinterrupting the synthesis reaction. It is also possible to use polymersamples or libraries of polymer samples that were prepared previouslyand stored. Typically, polymer libraries can be stored with agents toensure polymer integrity. Such storage agents include, for example,antioxidants or other agents effective for preventing cross-linking ofpolymer molecules during storage. Depending upon the polymerizationreaction, other processing steps may also be desired, all of which arepreferably automated. The polymerization scheme and/or mechanism bywhich the polymer molecules of the polymer component of the sample areprepared is not critical, and can include, for example, reactionsconsidered to be addition polymerization, condensation polymerization,step-growth polymerization, and/or chain-growth polymerizationreactions. Viewed from another aspect, the polymerization reaction canbe an emulsion polymerization or a dispersion polymerization reaction.Viewed more specifically with respect to the mechanism, thepolymerization reaction can be radical polymerization, ionicpolymerization (e.g., cationic polymerization, anionic polymerization),and/or ring-opening polymerization reactions, among others. Non-limitingexamples of the foregoing include, Ziegler-Natta or Kaminsky-Sinnreactions and various copolymerization reactions. Polymerization productmixtures can also be prepared by modification of a polymeric startingmaterials, by grafting reactions, chain extension, chain scission,functional group interconversion, or other reactions.

The sample size is not narrowly critical, and can generally vary,depending on the particular characterization protocols and systems usedto characterize the sample or components thereof. Typical sample sizescan range from about 0.1 μl to about 1 ml, more typically from about 1μl to about 1000 μl, even more typically from about 5 μl to about 100μl, and still more typically from about 10 μl to about 50 μl. Agenerally preferred sample size for flow characterization systems and,particularly for liquid chromatography, is a sample size of about 20 μl.

The polymer sample, such as a polymerization product mixture, can be araw, untreated polymer sample or can be pretreated in preparation forcharacterization. Typical sample preparation steps include preliminary,non-chromatographic separation of one or more components of a polymersample from other components, dilution, mixing and/or redissolution(e.g., from a solid state), among other operations. Preliminaryseparation methods can help remove large-scale impurities such as dust,coagulum or other impurities. Such separation methods can include, forexample: filtering (e.g., with a microfilter having pore sizes thatallow the passage of particles less than about 0.5 μm or 0.2 μm);precipitation of polymer components, monomer components and/or othersmall-molecule components, decanting, washing, scavenging (e.g., withdrying agents), membrane separation (e.g., diafiltration, dialysis),evaporation of volatile components and/or ion-exchange. The sample ispreferably diluted, if necessary, to a concentration range suitable fordetection. For typical liquid chromatography applications, for example,the sample concentration prior to loading into the liquid chromatographysystem can range from about 0.01 mg/ml to a neat sample, more typicallyfrom about 0.01 mg/ml to about 100 mg/ml, and even more typically fromabout 0.1 mg/ml to about 50 mg/ml. More specific concentration rangestypical for liquid chromatography samples include from about 0.1 mg/mlto about 20 mg/ml, and from about 0.5 mg/ml to about 5 mg/ml. Forflow-injection analysis systems, in which the sample is detected withoutsubstantial chromatographic separation thereof, much more dilutesolutions can be employed. Hence, the concentration can range from adetectable concentration level (for the particular detector employed) upto about 1 mg/ml, or more in some applications. Typical concentrationscan be about 1×10⁻² wt %, about 1×10⁻³ wt % or about 1×10⁻⁴ wt %. Mixingcan be required to increase the uniformity of a polymer sample emulsionor dispersion, and/or to integrate one or more additional componentsinto the polymer sample. Preparation steps, and particularly rapidpreparation techniques, can be an important aspect for combinatorialpolymer investigations—since polymer samples may be synthesized in aform not ideally suited for immediate characterization.

Pluralities of Polymer Samples/Libraries of Polymer Samples

A plurality of polymer samples comprises 2 or more polymer samples thatare physically or temporally separated from each other—for example, byresiding in different sample containers, by having a membrane or otherpartitioning material positioned between samples, by being partitioned(e.g., in-line) with an intervening fluid, by being temporally separatedin a flow process line (e.g., as sampled for process control purposes),or otherwise. The plurality of polymer samples preferably comprises 4 ormore polymer samples and more preferably 8 or more polymer samples. Fourpolymer samples can be employed, for example, in connection withexperiments having one control sample and three polymer samples varying(e.g., with respect to composition or process conditions as discussedabove) to be representative of a high, a medium and a low-value of thevaried factor—and thereby, to provide some indication as to trends. Fourpolymer samples are also a minimum number of samples to effect aserial-parallel characterization approach, as described above (e.g.,with two detectors operating in parallel). Eight polymer samples canprovide for additional variations in the explored factor space.Moreover, eight polymer samples corresponds to the number of parallelpolymerization reactors in the PPR-8™, being selectively offered as oneof the Discovery Tools™ of Symyx Technologies, Inc. (Santa Clara,Calif.). Higher numbers of polymer samples can be investigated,according to the methods of the invention, to provide additionalinsights into larger compositional and/or process space. In some cases,for example, the plurality of polymer samples can be 15 or more polymersamples, preferably 20 or more polymer samples, more preferably 40 ormore polymer samples and even more preferably 80 or more polymersamples. Such numbers can be loosely associated with standardconfigurations of other parallel reactor configurations (e.g., thePPR-48™, Symyx Technologies, Inc.) and/or of standard sample containers(e.g., 96-well microtiter plate-type formats). Moreover, even largernumbers of polymer samples can be characterized according to the methodsof the present invention for larger scale research endeavors. Hence, thenumber of polymer samples can be 150 or more, 400 or more, 500 or more,750 or more, 1,000 or more, 1,500 or more, 2,000 or more, 5,000 or moreand 10,000 or more polymer samples. As such, the number of polymersamples can range from about 2 polymer samples to about 10,000 polymersamples, and preferably from about 8 polymer samples to about 10,000polymer samples. In many applications, however, the number of polymersamples can range from about 80 polymer samples to about 1500 polymersamples. In some cases, in which processing of polymer samples usingtypical 96-well microtiter-plate formatting is convenient or otherwisedesirable, the number of polymer samples can be 96*N, where N is aninteger ranging from about 1 to about 100. For many applications, N cansuitably range from 1 to about 20, and in some cases, from 1 to about 5.

The plurality of polymer samples can be a library of polymer samples. Alibrary of polymer samples comprises an array of two or more differentpolymer samples spatially separated—preferably on a common substrate, ortemporally separated—for example, in a flow system. Candidate polymersamples (i.e., members) within a library may differ in a definable andtypically predefined way, including with regard to chemical structure,processing (e.g., synthesis) history, mixtures of interactingcomponents, purity, etc. The polymer samples are spatially separated,preferably at an exposed surface of the substrate, such that the arrayof polymer samples are separately addressable for characterizationthereof. The two or more different polymer samples can reside in samplecontainers formed as wells in a surface of the substrate. The number ofpolymer samples included within the library can generally be the same asthe number of samples included within the plurality of samples, asdiscussed above. In general, however, not all of the polymer sampleswithin a library of polymer samples need to be different polymersamples. When process conditions are to be evaluated, the libraries maycontain only one type of polymer sample. Typically, however, forcombinatorial polymer science research applications, at least two ormore, preferably at least four or more, even more preferably eight ormore and, in many cases most, and allowably each of the plurality ofpolymer samples in a given library of polymer samples will be differentfrom each other. Specifically, a different polymer sample can beincluded within at least about 50%, preferably at least 75%, preferablyat least 80%, even more preferably at least 90%, still more preferablyat least 95%, yet more preferably at least 98% and most preferably atleast 99% of the polymer samples included in the sample library. In somecases, all of the polymer samples in a library of polymer samples willbe different from each other.

The substrate can be a structure having a rigid or semirigid surface onwhich or into which the array of polymer samples can be formed ordeposited. The substrate can be of any suitable material, and preferablyconsists essentially of materials that are inert with respect to thepolymer samples of interest. Certain materials will, therefore, be lessdesirably employed as a substrate material for certain polymerizationreaction process conditions (e.g., high temperatures—especiallytemperatures greater than about 100° C.—or high pressures) and/or forcertain reaction mechanisms. Stainless steel, silicon, includingpolycrystalline silicon, single-crystal silicon, sputtered silicon, andsilica (SiO₂) in any of its forms (quartz, glass, etc.) are preferredsubstrate materials. Other known materials (e.g., silicon nitride,silicon carbide, metal oxides (e.g., alumina), mixed metal oxides, metalhalides (e.g., magnesium chloride), minerals, zeolites, and ceramics)may also be suitable for a substrate material in some applications.Organic and inorganic polymers may also be suitably employed in someapplications of the invention. Exemplary polymeric materials that can besuitable as a substrate material in particular applications includepolyimides such as Kapton™, polypropylene, polytetrafluoroethylene(PTFE) and/or polyether etherketone (PEEK), among others. The substratematerial is also preferably selected for suitability in connection withknown fabrication techniques. As to form, the sample containers formedin, at or on a substrate can be preferably, but are not necessarily,arranged in a substantially flat, substantially planar surface of thesubstrate. The sample containers can be formed in a surface of thesubstrate as dimples, wells, raised regions, trenches, or the like.Non-conventional substrate-based sample containers, such as relativelyflat surfaces having surface-modified regions (e.g., selectivelywettable regions) can also be employed. The overall size and/or shape ofthe substrate is not limiting to the invention. The size and shape canbe chosen, however, to be compatible with commercial availability,existing fabrication techniques, and/or with known or later-developedautomation techniques, including automated sampling and automatedsubstrate-handling devices. The substrate is also preferably sized to beportable by humans. The substrate can be thermally insulated,particularly for high temperature and/or low-temperature applications.In preferred embodiments, the substrate is designed such that theindividually addressable regions of the substrate can act aspolymerization reaction vessels for preparing a polymerization productmixture (as well as sample containers for the two or more differentpolymer samples during subsequent characterization thereof. Glass-lined,96-well, 384-well and 1536-well microtiter-type plates, fabricated fromstainless steel and/or aluminum, are preferred substrates for a libraryof polymer samples. The choice of an appropriate specific substratematerial and/or form for certain applications will be apparent to thoseof skill in the art in view of the guidance provided herein.

The library of polymer materials can be a combinatorial library ofpolymerization product mixtures. Polymer libraries can comprise, forexample, polymerization product mixtures resulting from polymerizationreactions that are varied with respect to, for example, reactantmaterials (e.g., monomers, comonomers), catalysts, catalyst precursors,initiators, additives, the relative amounts of such components, reactionconditions (e.g., temperature, pressure, reaction time) or any otherfactor affecting polymerization. Design variables for polymerizationreactions are well known in the art. See generally, Odian, Principles ofPolymerization, 3rd Ed., John Wiley & Sons, Inc. (1991). A library ofpolymer samples may be prepared in arrays, in parallel polymerizationreactors or in a serial fashion. Exemplary methods and apparatus forpreparing polymer libraries—based on combinatorial polymer synthesisapproaches—are disclosed in copending U.S. patent application Ser. No.09/211,982 of Turner et al. filed Dec. 14, 1998, copending U.S. patentapplication Ser. No. 09/227,558 of Turner et al. filed Jan. 8, 1999,copending U.S. patent application Ser. No. 09/235,368 of Weinberg et al.filed Jan. 21, 1999, and copending U.S. provisional patent applicationSer. No. 60/122,704 entitled “Controlled, Stable Free Radical Emulsionand Water-Based Polymerizations”, filed Mar. 9, 1999 by Klaerner et al.See also, PCT Patent Application WO 96/11878.

The libraries can be advantageously characterized directly, withoutbeing isolated, from the reaction vessel in which the polymer wassynthesized. Thus, reagents, catalysts or initiators and other additivesfor making polymers may be included with the polymer sample forcharacterization or screening.

While such methods are preferred for a combinatorial approach to polymerscience research, they are to be considered exemplary and non-limiting.As noted above, the particular polymer samples characterized accordingto the methods and with the apparatus disclosed herein can be from anysource, including, but not limited to polymerization product mixturesresulting from combinatorially synthesis approaches.

Non-Polymer Samples

Although the primary applications of the present invention are directedto combinatorial polymer science research and/or quality control forindustrial polymer synthesis or processing protocols, some aspects ofthe invention can have applications involving non-polymer samples. Anon-polymer sample can be a material that comprises an organic or aninorganic non-polymer element or compound. Oligomers are considered tobe polymers rather than non-polymers. The non-polymer molecule is, insome cases, preferably a non-biological non-polymer element or compound.Such non-biological non-polymer elements or compounds includenon-polymer elements or compounds other than those having awell-characterized biological activity and/or a primary commercialapplication for a biological field (e.g., steroids, hormones, etc.).More particularly, such non-biological, non-polymer elements orcompounds can include organic or inorganic pigments, carbon powders(e.g., carbon black), metals, metal oxides, metal salts, metal colloids,metal ligands, etc, without particular limitation.

Detectors/Detected Properties/Determined Properties

A polymer sample is characterized by detecting a property of the polymersample, or by detecting a property of a component (e.g., a polymercomponent, a monomer component) of the polymer sample. In many cases,the property is detected over a period of time, such that a variation inthe property can be observed or detected or the rate of change ofvariation of a property can be observed or detected. In the generalcase, the detected property can be any property which can provide ascientifically meaningful basis of comparison between two differentpolymer samples or between two different polymer components—eitherdirectly, or after being correlated to a specific characterizingproperty of interest. The detected property can be a chemical propertyor a physical property of the polymer sample or component thereof. Inpreferred applications, an optical property of the polymer sample or acomponent thereof can be detected. For example, an amount, frequency,intensity or direction of an incident light that is refracted,scattered, and/or absorbed by the polymer sample or a component thereofmay be detected. Other properties, such as pressure or other factorsaffecting a particular characterizing property of interest (e.g.,viscosity) can likewise be detected.

With reference to FIGS. 2A and 2B (discussed in greater detail below), aproperty of a polymer sample or of a component thereof, such as achromatographically separated component thereof, can be detected in aflow characterization system with one or more detectors 130. Inpreferred embodiments, a property of a polymer sample or of a componentthereof is detected with an optical detector such as a refractive-indexdetector, an ultraviolet-visual detector, a photodiode array detector, astatic-light-scattering detector, a dynamic-light-scattering detector,and/or an evaporative-light-scattering detector—also known as anevaporative mass detector (EMD). Other detectors (e.g., a capillaryviscometer detector, photodiode array detector (PDAD), infra-reddetector, fluorescence detector, electrochemical detector, conductivitydetector, etc.) can likewise be employed in connection with the presentinvention. The particular nature of the detector (e.g., shape and/orconfiguration of a detection cavity 131 within the detector) is notgenerally critical.

The protocols for characterizing one or more polymer samples preferablyfurther comprise determining a property of interest from the detectedproperty. The physically-detected properties, such as the capability ofthe polymer sample or component thereof to refract, scatter, emit orabsorb light can be correlated to properties of interest. Suchproperties of interest include, without limitation, weight-averagemolecular weight, number-average molecular weight, viscosity-averagemolecular weight, peak molecular weight, approximate molecular weight,polydispersity index, molecular-weight-distribution shape, relative orabsolute component concentration, chemical composition, conversion,concentration, mass, hydrodynamic radius (R_(h)), radius of gyration(R_(g)), chemical composition, amounts of residual monomer, presence andamounts of other low-molecular weight impurities in polymer samples,particle or molecular size, intrinsic viscosity, molecular shape,molecular conformation, and/or agglomeration or assemblage of molecules.The correlation between a detected property and a determined property ofinterest can be based on mathematical models and/or empiricalcalibrations. Such correlation methods are generally known in the art,and are typically incorporated into commercially-availablechromatographic detectors and/or detector or data-acquisition software.

For combinatorial polymer science research applications, as well asother applications, the characterization protocols can be effected todetermine at least a weight-average molecular weight as acharacterization property of primary importance. Other characterizationproperties of interest of substantial importance, include number-averagemolecular weight, polydispersity index, andmolecular-weight-distribution shape. For polymer samples that arepolymerization product mixtures, another characterization property ofsubstantial importance is conversion data for the polymerizationreaction, typically expressed as % monomer converted into polymer. Thecomposition of the polymer sample or of particular components thereof(e.g., polymer components) can also be of substantial importance.

For determining weight-average molecular weight from detectedproperties, a liquid chromatography system or a flow-injection analysissystem can advantageously employ a single detector or a combination oftwo or more detectors. In a single-detector embodiment, for example, adynamic light-scattering (DLS) detector can be used by itself todetermine an average hydrodynamic radius or a distribution ofhydrodynamic radii from the detected scattered light. The hydrodynamicradii can, in turn, be correlated to an average molecular weight or amolecular weight distribution. In a two-detector embodiment, forexample, a static-light scattering (SLS) detector (where the detectedscattered light is a function of weight-average molecular weight(M_(w)), concentration (C) and the square of the refractive indexincrement, (dn/dC)²) can be combined with a refractive index (RI)detector (where the detected refracted light is a function of (C) and(dn/dC)), with an ultraviolet/visible light absorbance (UV/VIS) detector(where the detected absorbed light is a function of (C)), or with anevaporative light scattering detector (ELSD) (where the detectedscattered light is a function of (C)). In another embodiment, asingle-detector or multiple detectors (e.g., SLS) can detect theintensity of light scattered by the sample or sample component at two ormore different angles, which can be correlated to molecular weight.

For polymer samples that are polymerization product mixtures, conversiondata for the polymerization reaction of which the sample isrepresentative can be determined by chromatographically resolving thepolymer component(s) and monomer component(s), determining amolecular-weight distribution for such components, integrating areasunder the respective peaks, and then comparing the integrated peak areas(e.g., using response factors for particular components and detectoremployed). Another approach for calculating conversion involvesconverting the polymer-peak area into polymer concentration or massusing a concentration-detector response calibration plot, and thencomparing the portion of the polymer mass or concentration found in thesample to the expected mass or concentration assuming 100%stoichiometric conversion. Composition data for a polymer sample can bedetermined from the consumption of monomer or comonomers or,alternatively, from a retention time per volume of the polymer peak or afraction thereof.

Advantageously, an ELSD detector, or other detectors that are notparticularly sensitive to low-molecular weight components of a polymersample, can be advantageously employed in connection with the flowcharacterization protocols of the invention to achieve a highsample-throughput. As discussed in greater detail below, detectors thatare insensitive to low-molecular weight components can be advantageouslyemployed in connection with rapid-serial overlapping techniques.Moreover, because the ELSD is also less sensitive to temperaturevariations than other types of mass detectors (e.g., RI detector) and isnot required to be in thermal equilibrium with the sample beingdetected, an ELSD detector can be employed advantageously in connectionwith high-temperature polymer characterization systems. Hence, detectinga property of a polymer sample or a component there of with an ELSD orwith other low-MW insensitive or less temperature sensitive massdetectors provides a further aspect for improving the samplethroughput—particularly for a liquid chromatography system 10 or aflow-injection analysis system 20.

The aforementioned characterizing properties of interest can, oncedetermined, be mathematically combined in various combinations toprovide figures of merit for various properties or attributes ofinterest. In particular, for example, molecular weight, conversion andpolydispersity index can be evaluated versus polymerization process timeto provide mechanistic insights as to how polymers are formed. Othercombinations of the fundamental characterization properties of interestwill be apparent to those of skill in the art.

Specific applications and/or combinations of detectors, as well ascorrelation protocols, are discussed in greater detail below.

Sample-Throughput

For methods directed to characterizing a plurality of samples, aproperty of each of the samples or of one or more components thereof isdetected—serially or in a parallel, serial-parallel or hybridparallel-serial manner—at an average sample throughput of not more thanabout 10 minutes per sample. As used in connection herewith, the term“average sample throughput” refers to the sample-number normalized total(cumulative) period of time required to detect a property of two or morepolymer samples with a characterization system. The total, cumulativetime period is delineated from the initiation of the characterizationprocess for the first sample, to the detection of a property of the lastsample or of a component thereof, and includes any interveningbetween-sample pauses in the process. The sample throughput is morepreferably not more than about 8 minutes per sample, even morepreferably not more than about 4 minutes per sample and still morepreferably not more than about 2 minutes per sample. Depending on thequality resolution of the characterizing information required, theaverage sample throughput can be not more than about 1 minute persample, and if desired, not more than about 30 seconds per sample, notmore than about 20 seconds per sample or not more than about 10 secondsper sample, and in some applications, not more than about 5 seconds persample and not more than about 1 second per sample. Sample-throughputvalues of less than 4 minutes, less than 2 minutes, less than 1 minute,less than 30 seconds, less than 20 seconds and less than 10 seconds aredemonstrated in the examples. The average sample-throughput preferablyranges from about 10 minutes per sample to about 10 seconds per sample,more preferably from about 8 minutes per sample to about 10 seconds persample, even more preferably from about 4 minutes per sample to about 10seconds per sample and, in some applications, most preferably from about2 minutes per sample to about 10 seconds per sample.

A sample-throughput of 10 minutes per sample or less is important for anumber of reasons. Flow-characterization systems that detect a propertyof a polymer sample or of a component thereof at the aforementionedsample throughput rates can be employed effectively in a combinatorialpolymer research program. From a completely practical point of view, thecharacterization rates are roughly commensurate with reasonably-scaledpolymer sample library synthesis rates. It is generally desirable thatcombinatorial screening systems, such as the polymer characterizationprotocols disclosed herein, operate with roughly the same samplethroughput as combinatorial synthesis protocols—to prevent a backlog ofuncharacterized polymerization product samples. Hence, because moderatescale polymer-synthesis systems, such as the Discovery Tools™ PPR48™(Symyx Technologies, Santa Clara Calif.), can readily prepare polymerlibraries with a sample-throughput of about 100 polymer samples per day,a screening throughput of about 10 minutes per sample or faster isdesirable. Higher throughput synthesis systems demand highercharacterization throughputs. The preferred higher throughput values arealso important with respect to process control applications, to providenear-real time control data. It is possible, moreover, that a particularsample being characterized may include component that are themselvesdifferent analytes of interest, such that the per-analyte throughput forthe characterization system can be significantly higher than theper-sample throughput thereof.

Additionally, as shown in connection with the examples provided herein,the characterization of polymer samples at such throughputs can offersufficiently rigorous quality of data, especially weight-averagemolecular weight, to be useful for scientifically meaningful explorationof the polymer compositional and/or polymerization reaction conditionsresearch space. Specifically, at sample throughputs ranging from about10 minutes per sample to about 8 minutes per sample, the polymer sampleor one or more components thereof can be characterized with respect toweight-average molecular weight, number-average molecular weight,polydispersity index, molecular weight distribution shape, andconversion information—all at reasonably high quality resolution. At asample throughput ranging between about 8 minutes per sample to about 2minutes per sample, the polymer sample or one or more components thereofcan be characterized with respect to weight-average molecular weight—atreasonably high quality resolution, and with respect to number-averagemolecular weight, polydispersity index, molecular weight distributionshape, and conversion information—all with good quality resolution. SeeExample 17. At a sample throughput ranging between about 2 minutes persample to about 1 minute per sample, the polymer sample or one or morecomponents thereof can be characterized with respect to weight-averagemolecular weight and conversion information—at reasonably high qualityresolution, and with respect to number-average molecular weight,polydispersity index, and molecular weight distribution shape—all withmoderate quality resolution. See Example 16. At a sample throughputranging between about 1 minute per sample to about 30 seconds persample, the polymer sample or one or more components thereof can becharacterized with respect to weight-average molecular weight—withmoderate quality resolution. See Example 15.

Hence, the average sample-throughput can range, in preferred cases, fromabout 10 minutes per sample to about 8 minutes per sample, from about 8minutes per sample to about 2 minutes per sample, from about 2 minutesper sample to about 1 minute per sample, from about 1 minute per sampleto about 30 seconds per sample and from about 1 minute per sample toabout 10 seconds per sample, with preferences depending on the qualityof resolution required in a particular case. For example, in someresearch strategies, the very high sample throughputs can be effectivelyemployed to efficiently identify a polymer sample or component thereofhaving a particularly desired property (e.g., such as weight-averagemolecular weight). In short, the search can be accelerated for theparticular property of research interest.

Specific protocols, systems and devices for achieving the aforementionedaverage sample throughput values for a plurality of polymer samples arediscussed and exemplified in greater detail below.

Flow Characterization Systems

In a preferred approach, a plurality of polymer samples arecharacterized by serially detecting a property of a plurality of polymersamples or of components thereof in a flow characterization system, suchas a liquid chromatography system or a related, flow-injection analysissystem, at an average sample-throughput of not more than about 10minutes per sample. Unlike traditional flow characterization protocols,which are designed to achieve universality with respect to polymer typeand with respect to quality of information—without substantial concernfor sample throughput, the high-throughput protocols disclosed andclaimed herein achieve high sample throughput, while optimizing qualityand universality to the extent necessary for the particular application.Rapid characterization for individual samples and/or for a plurality ofsamples are achieved, in general, by improving the efficiency ofsampling (polymer sample withdrawal, preparation, and delivery),chromatographic separation (for liquid chromatography systems) anddetection. As such, the protocols of the invention can be advantageouslyemployed, inter alia, for combinatorial polymer research and/or for nearreal time process control applications.

Liquid Chromatography Systems/Flow-Injection Analysis Systems—Overview

The polymer samples are preferably characterized according to themethods of the present invention with a flow characterization system. Asused herein, the term “flow characterization system” refers to a polymercharacterization system in which a polymer sample flows into a detectioncavity of a flow-through detector, a property of the polymer sample orof a component thereof is detected while the sample (or a portionthereof) resides in the detection cavity, and the polymer sample flowsout of the detection cavity. The flow-through detector can also beinterchangeably referred to as a continuous-flow detector. Aflow-through detector may have more than one detection cavity, and theflow characterization system may have more than one flow-throughdetector. As referred to herein, an individual flow-characterizationsystem has a single common flow path, as delineated by a common point ofsample injection (typically, through an injection valve) to a commonpoint of sample exhaust (typically, through a sample effluent port, andusually leading to a waste collection container). The flow path of anindividual flow-characterization system may, nonetheless, splitinternally within the system (e.g., with a flow-through detector havingmultiple detection cavities—such as with capillary-type detectioncavities.

Flow characterization systems can be broadly classified, for purposes ofthe present invention, as liquid chromatography systems andflow-injection analysis systems. Liquid chromatography systems are flowcharacterization systems that effect at least some chromatographicseparation of a polymer sample prior to detection of the sample or ofcomponents thereof in a flow-through detector. Flow-injection analysissystems are flow characterization systems without substantialchromatographic separation of the sample prior to detection with theflow-through detector. Flow-injection analysis systems can, however,include apparatus for non-chromatographic separations (e.g.,filtration). Moreover, a polymer sample can be prepared, prior toflow-injection analysis (or prior to liquid chromatography), byseparating one or more components of the raw sample from othercomponents thereof.

Briefly, with reference to FIG. 2A, a liquid chromatography system 10comprises an injection valve 100 (sometimes referred to as an injectionloop) having an injection port 108, a chromatographic column 102, aflow-through detector 130, and an effluent port 141. An in-line filter104, additional injection ports 108′, additional chromatographic columns102 and/or additional flow-through detectors 130 can also be included inthe system 10. Additionally, switches (e.g., automated switches) can beincluded to switch between various options with respect to filters 104,columns 102, detectors 130. In operation, a mobile-phase fluid is pumpedfrom a mobile-phase reservoir 114 by pump 116 through the injectionvalve 100, chromatographic column 102 and detector 130. The pump 116 canbe controlled with a microprocessor 134. The mobile phase can beexhausted from the system via effluent port 141 into a waste collectioncontainer 140. A polymer sample is loaded into the injection valve 100through the injection port 108, and the loaded sample is injected intothe mobile phase of the chromatographic system. The injected sample ischromatographically separated in the chromatographic column 102. Aproperty of the polymer sample, and/or of one or more separatedcomponents thereof, is then detected while the sample resides in adetection cavity 131 of the detector 130. A microprocessor (e.g.,computer) 134 is typically in electronic communication with the detectorto collect, process and analyze the data obtained therefrom. While thesame microprocessor 134 is shown in the figure for pump 116 control anddata acquisition, these functions could be effected with separatemicroprocessors 134.

With reference to FIG. 2B, a flow-injection analysis system 20 cancomprise an injection valve 100 having an injection port 108, aflow-through detector 130 and an effluent port 141. The flow-injectionanalysis system can also include an in-line filter 104, and can haveadditional injection ports 108 and/or flow-through detectors 130. Inoperation, a mobile-phase fluid is pumped from a mobile-phase reservoir114 by pump 116 through the injection valve 100, filter 104 (if present)and detector 130. The pump 116 can be controlled with a microprocessor134. The mobile phase can be exhausted from the system via effluent port141 into to a waste collection container 140. A polymer sample is loadedinto the injection valve 100 through the injection port 108, and theloaded sample is injected into the mobile phase of the flow-injectionanalysis system. The injected sample is optionally filtered in thefilter 104, and then a property of the polymer sample, and/or ofcomponents thereof, is then detected while the sample resides in adetection cavity 131 of the detector 130. A microprocessor (e.g.,computer) 134 is typically in electronic communication with the detectorto collect and analyze the data obtained therefrom. Although the samemicroprocessor 134 is shown in the figure for pump 116 control and dataacquisition, these functions could be effected with separatemicroprocessors 134.

The components of the liquid chromatography system 10 and theflow-injection-analysis system 20 are described more specifically below.The description of components common for each of the systems 10, 20(e.g., injection valves 100) are applicable to each such system, unlessspecifically designated otherwise in the context of particularlydescribed embodiments.

Reservoir/Pumps

Referring again to FIGS. 2A and 2B, the reservoir 114 of a flowcharacterization system can be of any suitable design and capacity, andtypically has a volume of about 4 liters. The particular mobile-phasefluid to be included in the reservoir 114 for the flow characterizationsystem can be selected in view of the polymer sample, detector, desiredflowrates, and liquid chromatography systems, further in view of thechromatographic separation technique being employed. Exemplarymobile-phase fluids for liquid chromatography systems (e.g., GPC,precipitation-redissolution chromatography, adsorption chromatographyand reverse-phase chromatography) and for flow-injection analysissystems are discussed below. The pump 116 can be of any type and sizesuitable to provide a motive force for the mobile-phase fluid throughthe flow-characterization systems 10, 20. Typical high-pressure liquidchromatography pumps, available commercially from various sources, suchas Waters Model No. 515 (Milford, Mass.) can be employed. The flowcharacterization systems 10, 20 can include additional reservoirs 114,and additional pumps 116 to provide more than one mobile-phase fluid, toprovide a mobile-phase composition gradient or, as discussed below, toprovide a mobile-phase temperature gradient.

Injection Valve

The injection valve 100 comprises one or more injection ports 108, oneor more sample loops, one or more mobile-phase inlet ports 101, and oneor more mobile-phase outlet ports 103. The polymer sample can beinjected directly through an injection port 108 into the mobile phaseflowing through the injection valve 100. In preferred embodiments,however, the injection valve 100 is an injection port valve typical ofthose used for a high pressure liquid chromatography system. As used inthis context, and with application to both liquid chromatography systems10 of the invention and flow-injection analysis systems 20 of theinvention, “high pressure” refers to internal system pressures (e.g.,mobile-phase pressures) above atmospheric pressure, typically rangingfrom about 0 psig to about 6000 psig, preferably from about 10 psig toabout 4000 psig, and more typically from about 100 psig to about 2000psig.

With reference to FIG. 3, the injection valve 100 can be an 8-portinjection port valve 210 (100) that operates as follows. Numerals inparenthesis refer to corresponding parts of the injection valve of FIGS.2A and 2B. A first polymer sample is loaded directly into an injectionport 108 or indirectly through a loading port 204, transfer line 206 andthe injection port 108 at relatively low pressure compared.to thepressure of the mobile phase. The loading port 204 can be adapted insize to accommodate one or more injection probes (tips) of a manual oran automated sample delivery unit (e.g., an auto-sampler). When the8-ported valve is in valve position “A” (with internal flow-paths forthe valve indicated by solid lines), the first polymer sample is loadedinto a sample loop 205A while the mobile phase flows through the valvevia mobile-phase inlet port 101 (the flow-in port), sample loop 205B,and mobile-phase outlet port 103 (the flow-out port). The sample loops205A and 205B can be of equal volume. A waste port 207 can be employedfor receiving any overflow sample and/or for flushing the valve aftereach sample, if necessary. When the injection valve 210 is switched tothe valve “B” position (with internal flow-paths for the valve nowindicated by the dashed lines), the mobile phase then flows through thevalve via mobile-phase inlet port 100, sample loop 205A, andmobile-phase outlet port 103, and the first polymer sample is therebyinjected into the mobile phase of the liquid chromatography system 10 orflow-injection analysis system 20. While the first polymer sample isbeing injected from sample loop 205A into the mobile phase of the flowcharacterization system, a second polymer sample can be loaded intosample loop 205B, ready to be injected once the valve is switched backto valve position A. Eight-ported valves, such as represented in FIG. 3,can be purchased from Valco Instruments Co. Inc. (Houston, Tex.), andthe purchased valve fittings can be modified as described above for usein connection with a flow characterization system. An eight portinjection valve 210 is a preferred injection valve 100 because the twosample loops 205A, 205B allow the flow characterization system to beready for sample loading at all times (i.e., has a load/loadcapability). As such, the eight-port valve is faster than, for example,a six port valve (e.g., a valve having only a single load position and asingle inject position), and therefore, the eight-port injection valveprovides one aspect for improving the sample throughput for a liquidchromatography system 10 or a flow-injection analysis system 20. Whilethe eight-port valve 210 depicted schematically in FIG. 3 is a preferredconfiguration, other high-pressure injection valves can also be suitablyemployed, including, without limitation, valves having a greater orlesser number of ports. Typically, however, a high-pressure injectionvalve will have from 6 to 24 ports.

Referring to FIG. 2A, FIG. 2B and FIG. 3, the injection valve 100 (210)can be configured to have more than one injection port 108, 108′ or asingle injection port 108, and in either case, the single or multipleinjection ports 108, 108′ can be in fluid communication with a number ofloading ports 204 via a number of transfer lines 206 in order to receivepolymer samples independently from a number of different injectionprobes, including, for example, a manual injection probes, and one ormore probes associated with automated delivery systems, such as one ormore robotic auto-samplers. The injection valve can also have a largernumber of sample loops with the same or with varying volumes, toaccommodate different samples sizes.

Sampling/Auto-Sampler

Sampling of a polymer sample refers to a plurality of steps whichinclude withdrawing a polymer sample from a sample container anddelivering at least a portion of the withdrawn sample to a polymercharacterization system. Sampling may also include additional steps,particularly and preferably, sample preparation steps. (See FIG. 1A). Inone approach, only one polymer sample is withdrawn into the auto-samplerprobe at a time and only one polymer sample resides in the probe at onetime. The one polymer sample is expelled therefrom (for samplepreparation and/or into the polymer characterization system) beforedrawing the next polymer sample. In an alternative approach, however,two or more polymer samples can be withdrawn into the auto-sampler probesequentially, spatially separated by a solvent, such that the two ormore polymer samples reside in the probe at the same time. Such a“candystriping” approach can provide for very high auto-samplerthroughputs for rapid introduction of the one or more samples into theflow characterization system.

The sample container from which the polymer sample is withdrawn is notcritical. The sample container can be, for example a sample-containingwell. The sample-containing well can be a sample vial, a plurality ofsample vials, or a sample-containing well within an array ofsample-containing wells (e.g., constituting a polymer sample library).The sample container can alternatively be a sample port from a sampleline in fluid communication with an industrial process line, such as apolymerization process line.

In the general case, sampling can be effected manually, in asemi-automatic manner or in an automatic manner. A polymer sample can bewithdrawn from a sample container manually, for example, with a pipetteor with a syringe-type manual probe, and then manually delivered to aloading port or an injection port of a polymer characterization system.In a semi-automatic protocol, some aspect of the protocol is effectedautomatically (e.g., delivery), but some other aspect requires manualintervention (e.g., withdrawal of polymer samples from a process controlline). Preferably, however, the polymer sample(s) are withdrawn from asample container and delivered to the characterization system in a fullyautomated manner—for example, with an auto-sampler.

A plurality of polymer samples, such as those included within a libraryof polymer samples, is preferably delivered to the injection valve 100,for loading into the flow characterization system, with an automaticdelivery device, such as an auto-sampler. As used herein, the term“auto-sampler” refers to an apparatus suitable for automated sampling ofpolymer samples for characterization, including automated withdrawal ofa polymer sample from a sample container, and automated loading of atleast a portion of the withdrawn sample into an injection port or aloading port of a flow characterization system (e.g. a liquidchromatography system).

Automated sampling equipment is available commercially for introducingmultiple samples into liquid flow systems in a serial manner. While suchcommercially-available auto-sampling equipment could be used with thisinvention, currently available systems have several drawbacks. First,commercially available auto-samplers typically operate with a singlepredefined rack or tray configuration, which contains vials in arectangular, linear, or rotary array. Samples are loaded manually andindividually into vials, and manually placed in the array for subsequentsampling. The combinatorial aspects of this invention, however, preferautomated sample preparation of vast numbers of samples, from a varietyof parallel vessel arrays or reactor blocks. Additionally, commercialauto-sampling equipment is not sufficiently rapid. Conventionalauto-samplers require up to several minutes per cycle to introduce apolymer sample into a flow characterization system—including steps suchas sample changing, drawing, loading, and cleaning of the system inpreparation for the next sample. (See comparative Ex. 1). For thepurposes of this invention, more rapid sample introduction isdesirable—preferably requiring much less than one minute per sample.Moreover, conventional commercially-available auto-sampling equipment isnot designed for complex sample preparation, including transfer,dilution, purification, precipitation, or other steps needed to prepareelements of a combinatorial array for characterization.

As such, aspects of this invention are directed to an auto-sampler andauto-sampling methods. In a preferred embodiment, with reference to FIG.4, an auto-sampler 200 can comprise a movable probe (tip) 201, typicallymounted on a support arm 203, a translation station 221 for providingthree-dimensional motion of the probe, and a microprocessor 222 forcontrolling three-dimensional motion of the probe between variousspatial addresses. The auto-sampler 200 preferably also comprises auser-interface (not shown) to allow for user programming of themicroprocessor 222 with respect to probe motion and manipulations. Theprobe 201 can have an interior surface defining a sample-cavity and aninlet port for fluid communication between the sample cavity and apolymer sample 20. The probe 201 is also adapted for fluid communicationwith an injection port 108 (FIG. 2A, FIG. 2B) or a loading port 204 of aflow characterization system. The support arm 203 is preferably an XYZrobotic arm, such as can be commercially obtained from Cavro ScientificInstruments, Inc. (Sunnyvale, Calif.) among others. To improvesmoothness of operation at high speeds, such XYZ robotic arms preferablyhave motions based on gradient variations rather than step-functionvariations, and preferably are belt-driven rather than shaft driven. Themicroprocessor 222 can be a computer and can be the same or differentfrom the microprocessor 134 (FIG. 2A, FIG. 2B) used to control thedetectors 130 (FIG. 2A, FIG. 2B) and data acquisition therefrom. Theauto-sampler can further comprise one or more pumps (not shown),preferably syringe pumps, for drawing and/or expelling liquids, andrelated connection lines (not shown) for fluid communication between thepumps, the probe 201, and liquid (e.g. solvent) reservoirs. Preferredembodiments include two or more syringe pumps—one with a relativelylower flowrate capacity and one with a relatively higher flowratecapacity. (See Ex. 1). Alternative pump configurations, such asperistaltic pumps, vacuum-pumps or other motive-force providing meanscan be used additionally or alternatively. Sampling throughputs may alsobe enhanced by using two or more robotic arms together (See Ex. 2). Itis likewise possible to have more two or more sample probes inconnection with a single robotic arm—for example, such as an array oftwo or more probes each capable of synchronized motion relative to eachother.

In operation, the microprocessor 222 of the auto-sampler 200 can beprogrammed to direct the auto-sampler 200 to withdraw a polymer sample20 (e.g., a polymer solution comprising a dissolved polymer) from asample container (e.g., a sample well) formed in a sample tray 202 intothe injection probe 201, and subsequently to direct the probe 201 to theloading port 204 for loading the sample into the characterization systemthrough transfer line 206. In preferred embodiments, the auto-samplercan be programmed to automatically sample each well of a library ofpolymer samples one after the other whereby a plurality of polymersamples are serially loaded into the flow characterization system, andsubsequently serially injected into the mobile phase of thecharacterization system in a plug flow fashion. Preferably, themicroprocessor 222 of the auto-sampler comprises a user-interface thatcan be programmed to allow for variations from a normal sampling routine(e.g., skipping certain elements at certain spatial addresses of alibrary). The auto-sampler 200 can also be controlled for manualoperation on an individual sample by sample basis.

The microprocessor 222 is also preferably user-programmable toaccommodate libraries of polymer samples having varying arrangements ofarrays of polymer samples (e.g., square arrays with “n-rows” by“n-columns”, rectangular arrays with “n-rows” by “m-columns”, roundarrays, triangular arrays with “r-” by “r-” by “r-” equilateral sides,triangular arrays with “r-base” by “s-” by “s-” isosceles sides, etc.,where n, m, r, and s are integers). More particularly, for example, withrespect to square or rectangular arrays, a two sets of samples (e.g.,libraries) having different spatial configurations can be sampled asfollows. First, an auto-sampler is programmed (e.g., via a userinterface module) with location information for a first set of samplescomprising a plurality of samples in a plurality of sample containers infirst spatial arrangement (e.g., “n-rows” by “m-columns”, where n and mare integers). The first set of samples are serially withdrawn fromtheir respective sample containers, and at least a portion of each ofthe withdrawn first set of samples are serially delivered to one or moreintended locations (e.g., a characterization system). The auto-sampleris then reprogrammed with location information for a second set ofliquid samples that comprise a plurality of samples in a plurality ofsample containers in second spatial arrangement (e.g., “p-rows” by“q-columns”, where p and q are integers). The second set of samples areserially withdrawn from their respective sample containers, and at leasta portion of each of the withdrawn second set of samples are seriallydelivered to one or more intended locations.

In a preferred protocol for sampling a plurality of polymer samples, anauto-sampler provides for rapid-serial loading of the plurality ofpolymer samples into a common injection port of an injection valve. Morespecifically, a plurality of polymer samples is sampled as follows. At afirst withdrawal time, t_(ASW1), a first polymer sample is withdrawnfrom a first sample container at a first location into a probe of anauto-sampler. At least a portion of the withdrawn first sample is thendelivered to an injection port of a polymer characterization system,either directly, or through a loading port and a transfer line. Afterdelivery of the first polymer sample, a second polymer sample is, at asecond withdrawal time, t_(ASW2), withdrawn from a second samplecontainer at a second location into the auto-sampler probe. At least aportion of the withdrawn second sample is then delivered (directly orindirectly) to the injection port of the polymer characterizationsystem. The auto-sampler cycle time, T_(AS), delineated by thedifference in time, t_(ASW2)−t_(ASW1), is preferably not more than about40 seconds, more preferably not more than about 30 seconds, even morepreferably not more than about 20 seconds, more preferably still notmore than about 10 seconds, and most preferably not more than about 8seconds. The cycle can then be repeated, as necessary, in an automatedmanner, for additional polymer samples included within the plurality ofpolymer samples. The operation of the auto-sampler in such a high-speed,rapid-serial manner provides another aspect for improving the samplethroughput for a liquid chromatography system 10 or a flow-injectionanalysis system 20.

The preferred protocol for sampling a plurality of polymer samples canalso include additional automated steps. Preferably for example, in aninterval of the sampling cycle defined by the period of time afterdelivery of at least a portion of the first polymer sample into aloading port or an injection port of a flow characterization system, andbefore withdrawal of the second polymer sample, a residual portion ofthe first sample still remaining in the sample cavity of theauto-sampler probe, if any, can be expelled therefrom, for example to awaste container. Additionally or alternatively, the auto-sampler probecan be cleaned during this interval of the sampling cycle. Cleaning theauto-sampler probe, in an automated fashion, can include flushing thesample cavity of the probe with a solvent source available to the probe,and then expelling the solvent into a waste container. Such withdrawaland expelling of a cleaning solvent can be repeated one or more times,as necessary to effectively limit the extent of cross-contaminationbetween the first and second polymer samples to a level that isacceptable. As an alternative or additional cleaning protocol, the probemay be immersed in a cleaning solution and moved around therein toeffectively rinse residual polymer sample from both the external portionof the probe and the sample cavity thereof. The expelling step and theone or more cleaning steps can be, and are preferably automated. Whileexpelling and cleaning steps are generally preferred, no cleaning may berequired for polymer characterization applications in which minor samplecross-contamination is acceptable for a rough characterization of thepolymer samples. The expelling and one or more cleaning steps can beeffected within the preferred sampling cycle times recited above.

Sample preparation steps can also be included in the preferred protocolfor sampling a plurality of polymer samples. The sample preparationsteps, examples of which are discussed more specifically below, arepreferably automated, preferably effected with the auto-sampler, and arepreferably effected within the preferred sample cycling times recitedabove.

Significantly, sample preparation steps (also referred to herein aspretreatment steps) for a plurality of samples are preferably integratedinto a rapid-serial sampling approach such that each of the preparedsamples is loaded into the polymer characterization system, andsubsequently characterized shortly after the sample-preparation stepsare completed. In preferred protocols, for example, the prepared samplesare injected into a mobile phase of polymer characterization systemwithin not more than about 30 seconds, more preferably not more thanabout 20 seconds, still more preferably not more than about 10 seconds,even more preferably not more than about 8 seconds, and most preferablynot more than about 5 seconds after preparation steps are complete. Thisapproach is unlike typical automated preparation protocols—developedprimarily for liquid samples other than the preferred non-biologicalpolymer samples. In known approaches, an entire plurality of liquidsamples is typically prepared before any of the plurality of liquidsamples is delivered to a characterization system. Although the knownconventional approach may be satisfactory for aqueous-based,non-volatile systems, such an approach is generally less preferred forcharacterizing polymer samples, which may include a volatileliquid-phase component or are worked up with preparation steps thatinclude volatile solvents. If the conventional approaches were appliedto a larger plurality (e.g. a number greater than about 8 polymersamples) of polymer samples having a volatile liquid-phase component,the time during which the prepared samples await delivery to the flowcharacterization system can result in a change in constituentconcentrations and, therefore, can effect the comparative basis betweendetected properties of different polymer samples. As an alternativeapproach, where parallel sample preparation is necessary or desired andthe sample may be stored for some period of time (e.g., more than about1 hour), it may be desirable to cover the sample containers having theprepared samples to minimize evaporation and protect againstcontamination (e.g., by dust). Preferably, the containers can be coveredwith a physically weak, chemically inert barrier such as Teflon™ tape,that can be pierced by the probe for sample withdrawal, thereby allowingneighboring covered samples to remain covered until immediately prior tosampling. As yet another alternative, for samples that may have lostsome of the solvent due to evaporation thereof, the solvent can bereplenished to a desired level immediately prior to loading of thesample into the characterization system.

Hence, a plurality of polymer samples, especially 8 or more polymersamples, are preferably sampled in a rapid-serial manner by drawing atleast a portion of a polymer sample from a sample container into a probeof an auto-sampler, expelling at least a portion of the drawn sample toa sample-preparation container, pretreating the expelled sample in thesample-preparation container to form a pretreated sample, drawing atleast a portion of the pretreated sample from the sample-preparationcontainer into the auto-sampler probe, delivering at least a portion ofthe pretreated sample mixture to a polymer characterization system, andthen serially repeating each of the immediately-aforementioned steps forthe plurality of polymer samples. In preferred protocols, such steps areeffected within the sampling cycle times discussed above. Suchrapid-serial withdrawal-preparation-delivery protocols are advantageousover prior art protocols, and as applied to a plurality of polymersamples provide another aspect for improving the sample throughput for aliquid chromatography system 10 or a flow-injection. analysis system 20.The preferred rapid-serial withdrawal-preparation-delivery protocol canalso optionally include, and will typically preferably include expellinga residual portion of 10 the pretreated sample from the auto-samplerprobe, and cleaning the auto-sampler probe after delivering at least aportion of the pretreated sample. The expelling and cleaning can beeffected as discussed above.

The particular sample-preparation (pretreatment) steps are not critical,and desired pretreatment protocols are well known in the art. Asdiscussed above in connection with the polymer sample, the pretreatingstep can comprise diluting the sample, separating one or more componentsof the sample from other components thereof, and/or mixing the sample.These steps can be, and are preferably, effected with an auto-sampler,for example, as specified in the following exemplary protocols.Variations and other approaches for automated sample preparation will beapparent to a person of skill in the art, and as such, the presentinvention is not limited by these exemplary protocols. A polymer samplemay be diluted with the auto-sampler to a concentration range suitablefor detection by combining the expelled sample with a diluting agent(e.g., solvent) in the sample-preparation container. Preliminary,non-chromatographic separation of one or more non-polymer components(e.g., impurities) from a polymer sample may be effected with anauto-sampler as follows. The expelled polymer sample can be combinedwith a polymer-component-precipitating (“poor”) solvent, in thesample-preparation container, whereby polymer components and/or alsoother components are precipitated, but impurities remain in the liquidphase (poor solvent) within the preparation container. Theimpurity-containing liquid phase is then removed from thesample-preparation container—for example, by withdrawing the liquidphase into the auto-sampler probe and then discharging the liquid phaseinto a waste container. Washing steps may then be effected. Afterwashing the probe, if applicable, and optionally filtering or decanting,the auto-sampler probe can be used to deliver apolymer-component-dissolving (“good”) solvent to the preparationcontainer, whereby the polymer component and monomer components areredissolved to form a prepared polymer solution. Mixing of a polymersample (e.g., with an additional component) can likewise be convenientlyeffected with the auto-sampler in a rapid manner. In one approach,mixing can be effected by inserting the auto-sampler probe into theliquid in the sample-preparation container, removing the auto-samplerprobe from the sample-preparation container, and repeating the steps ofinserting and removing the auto-sampler probe at least once, andpreferably until adequate mixing is achieved. In another auto-samplermixing approach, the polymer sample can be mixed by withdrawing at leasta substantial portion of a liquid phase from the sample-preparationcontainer into the auto-sampler probe, expelling the withdrawnliquid-phase back into the sample-preparation container, and repeatingthe steps of withdrawing and expelling from and to thesample-preparation container at least once, and preferably untiladequate mixing is achieved.

Filters/Pulse-Dampers

As noted above, aspects of sample preparation can also be effected“in-line” within the flow characterization system. Referring again toFIGS. 2A and 2B, for example, non-chromatographic separation can,optionally, be effected with one or more in-line filters 104. Thein-line filter 104 can be of any suitable dimensions and mesh size. Inone embodiment, a filter 104 can retain particles having a diameter ofmore than about 0.5 μm. In another embodiment, a filter 104 can retainparticles having a diameter of more than about 0.2 μm. Other sizes mayalso be employed, as suitable for a particular polymer sample and/orprocess application. Additional in-line filters can likewise beemployed. While shown in FIGS. 2A and 2B immediately downstream of theinjection valve 100, the particular location of the filter is notcritical. Moreover, the polymer sample could be filtered as apreparation step, prior to loading of the polymer sample into the flowcharacterization system. Other in-line systems, such as pulse-damperscan also be employed.

Chromatographic Separation—Chromatographic Column

After injection of a polymer sample into a stream of liquid serving as amobile phase of a liquid chromatography system, the polymer sample isintroduced into a chromatographic column containing a separation mediumhaving a stationary-phase for separation of one or more components ofthe polymer sample from other components thereof. Separation is effectedby selectively eluting one or more of the polymer components from thestationary-phase with a mobile-phase eluant. The degree of separation,also referred to as the resolution of the polymer sample components, canvary depending on the particular chemical nature of the polymer samplecomponents, and the quality of information required in the particularcharacterization application. In general, the separation performance ina given case can be controlled as a function of the columndesign/geometry, the stationary-phase media, and the elution conditionswith the mobile phase.

The particular design of a chromatographic column for liquidchromatography is, in the general case, not narrowly critical. A numberof columns known in the art can be employed in connection with thepresent invention—as purchased or with minor variations disclosedherein. In general, with reference to FIG. 2A, the chromatographiccolumn 102 of a liquid chromatography system 10 comprises an interiorsurface defining a pressurizable separation cavity having a definedvolume, an inlet port for receiving a mobile phase and for supplying apolymer sample to the separation cavity, and an effluent port fordischarging the mobile phase and the polymer sample or separatedcomponents thereof from the separation cavity. The separation cavity ispreferably pressurizable to pressures typically involved withhigh-pressure liquid chromatography—such pressures generally rangingfrom about atmospheric pressure to about 6000 psig (about 40 MPa). Insome preferred liquid-chromatography characterization methods, discussedin greater detail below, the chromatographic column can be relativelyshorter, and relatively wider, compared to traditional chromatographicseparation columns.

The chromatographic column 102 further comprises a separation mediumhaving a stationary-phase within the separation cavity. The separationmedium can consist essentially of a stationary-phase or can alsoinclude, in addition thereto, an inert support for the stationary phase.The column 102 can also comprise one or more fillers, frits (forseparation medium retention and/or for filtering), and various fittingsand features appropriate for preparing and/or maintaining the column forits intended application. The particular separation medium to beemployed as the stationary-phase is not critical, and will typicallydepend on the separation strategy for the particular chemistry of thepolymer samples of interest, as well as on the desired detection,sample-throughput and/or information quality. Typical stationary-phasemedia can be a bed of packed beads, rods or other shaped-particles, or amonolithic medium (typically greater than about 5 mm in thickness), eachof which can be characterized and optimized for a particular separationstrategy with respect to the material, size, shape, pore size, pore sizedistribution, surface area, solvent regain, bed homogeneity (for packedshaped-particles), inertness, polarity, hydrophobicity, chemicalstability, mechanical stability and solvent permeability, among otherfactors. Generally preferred stationary-phase include porous media(e.g., porous beads, porous monoliths), such as are suitable for gelpermeation chromatography (GPC), and media suitable forprecipitation-redissolution chromatography, adsorption chromatography,and/or reverse-phase chromatography. Non-porous particles or emptycolumns and/or capillaries with adsorptive walls can be used as well. Ifbeads are employed, spherical beads are preferred over other shapes.Particularly preferred stationary-phase media for polymercharacterization applications are disclosed in greater detail below, butcan generally include silica, cross-linked resins, hydroxylatedpolyglycidyl methacrylates,(e.g.,poly(2-3-dihydroxypropylmethacrylate)), poly(hydroxyethyl methacrylate),and polystyrenic polymers such as poly(styrenedivinylbenzene).

The mobile-phase fluid(s) employed to elute one or more polymercomponents from a chromatographic stationary-phase are not generallycritical, and can vary depending on the chemistry of the separationbeing effected. The mobile phase can be varied with respect tocomposition, temperature, gradient rates, flow-rates, and other factorsaffecting selectivity, speed of separation, peak capacity (e.g., maximumnumber of components that can be separated with a single run) and/orresolution of a polymer component. Exemplary mobile-phase fluids for GPCinclude tetrahydrofuran (THF), toluene, dimethylformamide, water,aqueous buffers, trichlorobenzene and dichlorobenzene. Exemplarymobile-phase fluids for precipitation-redissolution chromatographyinclude THF, methanol, hexane, acetone, acetonitrile and water. Foradsorption chromatography, the mobile phase can include, for example,hexane, isooctane, decane, THF, dichloromethane, chloroform,diethylether and acetone. For reverse-phase chromatography, the mobilephase can include water, acetonitrile, methanol and THF, among others.

Significantly, preferred mobile phase flow rates—for liquidchromatography and/or for flow-injection analysis systems—are typicallyfaster than flowrates employed conventionally for high-pressure liquidchromatography. The flowrates can vary, depending on the separationbeing effected, but can, in many instances, range from about 0.1 ml/minabout 25 ml/min, and preferably range from about 1 ml/min to about 25ml/min. It may be desirable, for some detector configurations, to splitoff a part of the sample-containing mobile phase such that the flow rateto a particular detector is reduced to an acceptable level. For liquidchromatography systems, such a split would typically occur after thecolumn and before the detector.

Microprocessors

Referring to FIG. 2A, FIG. 2B and FIG. 4, one or more microprocessorscan, as noted above, be employed for controlling every aspect of theflow characterization systems, including: the pump 116 (e.g.,mobile-phase flow-rate, flow-rate gradients, compositional gradients,temperature gradients, acceleration rates for such gradients); thereservoir 114 (e.g., temperature, level); the auto-sampler 200 (e.g.,movements between spatial position, timing thereof, sample selection,sample preparation, sampling pump flow-rates, and other operations), theinjection valve 100 (e.g., timing, selection of sample loops, etc.); thecolumn 102 (e.g., column selection (if multiple columns and automatedcolumn-switching valves are present), column temperature); the detector130 (e.g., data acquisition (e.g., sampling rate), data processing(e.g., correlation); the detector parameters (e.g., wavelength); and/oroverall system conditions (e.g., system pressure, temperature). Softwareis typically available from detector and/or liquid chromatography systemmanufacturers (e.g., MILLENIUM™ 2000 software available from Waters(Milford, Mass.).

Preferred Liquid Chromatography Protocols

An individual polymer sample is preferably characterized with a liquidchromatography system by withdrawing a polymer sample from a samplecontainer into a probe of an auto-sampler at a first withdrawal time,t_(ASW1). At least a portion of the withdrawn sample is then expelledfrom the auto-sampler probe into a liquid chromatography system and theloaded sample is injected into the mobile phase thereof. At least onesample component of the injected sample is separated from other samplecomponents thereof in a chromatographic column. At a second detectiontime, t_(LCD1), a property of at least one of the separated samplecomponents is detected. The characterization protocol can also includepretreating the withdrawn sample prior to injection, such pretreatingcomprising sample preparation steps as described. The steps ofwithdrawing the polymer sample, injecting at least a portion thereofinto the mobile phase of the liquid chromatography system,chromatographically separating one or more components of the sample, anddetecting a property of the sample or of a component thereof arepreferably controlled such that the period of time required tocharacterize the polymer sample, the liquid-chromatographycharacterization period, delineated by the difference in time,t_(LCD1)−t_(ASW1), is not more than about 4 minutes. Theliquid-chromatography characterization time is preferably less thanabout 4 minutes, and depending on the quality of information required,can be less than about 2 minutes, less than about 1 minute, less thanabout 30 seconds, less than about 20 seconds or less than about 10seconds. The rapid liquid chromatography protocols of the invention havecommercial application with respect to a single, individual polymersample, for example, in field-based research such as processtroubleshooting. As noted, however, substantial commercial applicationsrelate to pluralities of polymer samples.

A plurality of polymer samples is preferably characterized with a liquidchromatography system as follows. A first polymer sample is withdrawnfrom a first sample container, optionally pretreated in preparation forcharacterization, and then at least a portion thereof is loaded into aninjection valve of the liquid chromatography system. At a firstinjection time, t_(LCI1), the loaded first sample is injected from theinjection valve into a mobile phase of the liquid chromatography system.At least one sample component of the injected first sample ischromatographically separated from other components thereof in achromatographic column. A property, preferably an optical property, ofat least one of the separated sample components of the first sample isthen detected. One or more properties of interest (e.g., weight-averagemolecular weight, composition and/or conversion values) can bedetermined from the detected property of the first sample or componentthereof.

Meanwhile, a second polymer sample is withdrawn from a second samplecontainer. If the same withdrawal instrument is employed, the instrumentis preferably cleaned after loading the first sample into the injectionvalve and before withdrawing the second sample. The second sample isoptionally pretreated in preparation for characterization, and at leasta portion of the withdrawn second sample is then loaded into theinjection valve of the liquid chromatography system. At a secondinjection time, t_(LCI2), the loaded second sample is injected into themobile phase of the liquid chromatography system. At least one samplecomponent of the injected second sample is chromatographically separatedfrom other sample components thereof in the chromatographic column, andthen a property of at least one of the separated sample components ofthe second sample is detected. One or more properties of interest (e.g.,weight-average molecular weight, composition and/or conversion values)can be determined from the detected property of the second sample orcomponent thereof.

The steps of withdrawing the polymer sample from the sample container,optionally preparing the sample, loading the sample into the injectionvalve, injection of the sample into the mobile phase, chromatographicseparation of the polymer sample and/or detection of a separated samplecomponent are controlled such that the liquid chromatography cycle time,T_(LC), delineated as the difference in between sample injections intothe mobile phase of the liquid chromatography system, t_(LCI2)−t_(LCI1),is not more than about 10 minutes. The cycle time is preferably not morethan about 8 minutes, and can be, as discussed above depending on thedesired quality resolution of the detected property (or of properties ofinterest determined therefrom), less than about 4 minutes, less thanabout 2 minutes, less than about 1 minute, less than about 30 seconds,less than about 20 seconds and less than about 10 seconds.

Controlling the efficiency of chromatographic separation is an importantaspect of achieving high sample-throughput with acceptable informationquality. In general, the column geometry, stationary-phase (e.g.,permeability, porosity, size, shape, distribution, surface area, surfacechemistry), mobile-phase (e.g., eluant composition, eluant temperature,eluant flow rate, gradient profiles for eluant composition, temperatureand/or flowrate) are controlled such that the sample-throughput is notmore than about 10 minutes per sample. These factors are preferablycontrolled, individually, in combination with each other, or incombination with other factors, to achieve an average-sample throughputwithin the times and ranges previously specified. Generally, liquidchromatography relies upon separation based on a particular polymerproperty (e.g. size) or on a particular polymer composition (e.g.,chemistry). Separations to be effected based on size (e.g. hydrodynamicvolume) of a polymer sample component can preferably employ GPC mediaand protocols, somewhat less preferably precipitation-redissolution, andeven less preferably reverse-phase (hydrophobic) media or adsorption ornormal-phase (hydrophilic) media. Where the separation strategy is toeffect a separation based on the particular chemistry of the polymersample components, the adsorption, normal-phase and reverse-phasechromatography approaches are preferably employed, whileprecipitation-redissolution approaches are somewhat less preferred andGPC approaches are even less preferred. More than one type of column orseparation method may be combined, such as GPC in combination with oneof adsorption chromatography, reverse-phase chromatography orprecipitation-redissolution chromatography. Such approaches allowssimultaneous, rapid separation of polymeric components by size (e.g.,R_(h)) and separation of non-polymeric smaller size components bychemistry (e.g., polarity). Because polymer separation occurs, thisembodiment allows for measurements of distributions of properties, suchas distribution of chemical composition or a distribution of molecularweight for each sample.

The particular configuration of the liquid chromatography system used inconnection with the present case is not, in the general case, narrowlycritical. An exemplary liquid chromatography system is depictedschematically in FIG. 6. Briefly, the liquid chromatography system 10comprises an injection valve 100, chromatographic column 102, andcontinuous-flow-through detectors 130, 132. A polymer sample 20 can beloaded into the injection valve 100 from one or more places, eitherdirectly via injection ports 108, 108′ or indirectly through a loadingport 204 and transfer line 206. First, a polymer sample 20 (or aplurality of polymer samples) may be loaded with a robotic auto-sampler104 that is external to a heated environment (e.g., oven 112) bywithdrawing a sample from, for example, a library of samples 106 stagedfor auto-sampling, and injecting the sample into the loading port 204. Asample can also be loaded into the injection valve 100 through a manualinjection port 108. As another alternative, a polymer sample can beloaded into the injection valve by an auto-sampler 110 that is inside(i.e., internal to) the heated environment (e.g., controlled temperatureoven 112). One or more mobile-phase fluids (e.g., solvents) can bestored in reservoirs 114, 120 having dedicated pumps 116, 118 thatprovide the pressure for pumping the mobile-phase fluids through thesystem 10—including column 102 and detectors 130, 132. The pumps 116,118 can be controlled by a computer 122. If a mobile-phase temperaturegradient is desired, (e.g., in applications discussed below), a coldermobile-phase fluid can be in one reservoir and a hotter mobile-phasefluid can be in another reservoir. For example, a hotter solvent cancome from reservoir 114 via pump 116 and the colder solvent can comefrom reservoir 120 via pump 118. In such cases, valves 124, 126 can beappropriately manipulated—manually or automatically—to open and/orclose, preferably allowing for injection of the colder solvent justprior to the column 102. Check valves 123 can also be used for flowcontrol. The solvent can, in this embodiment, remain cold because itwill not enter the oven 112 until just prior to injection. Afterchromatographic separation in column 102, the polymer sample orcomponents thereof may be detected by one or more detectors 130, 132.The detectors can be both internal to the heated environment, as shownin FIG. 6, or alternatively, one or more or all of the detectors canreside externally to the heated environment. The detectors arepreferably connected to a computer 134 to collect and process the dataobtained from the detectors. In an exemplary configuration, detector 130can be a light scattering detector and detector 132 can be a refractiveindex detector or an evaporative mass detector. Following detection, thepolymer sample can be exhausted to a waste container 140.

The following protocols can be effectively applied individually, or incombination, and moreover, can find applications with low-, ambient-, orhigh-temperature characterization protocols.

Column Geometry

In some preferred liquid-chromatography characterization methods, thechromatographic column can be relatively shorter, and relatively wider,compared to traditional chromatographic separation columns. The typicalgeometry of a conventional column is long and narrow, ranging from about4-8 mm in diameter and from about 30-50 cm in length, respectively.Typically, three or four columns are employed in series for eachseparation.

Unlike conventional approaches, preferred liquid chromatographic methodsof the present invention can employ columns that are relatively shortand wide. More specifically, the chromatographic column can have anaspect ratio ranging from about 0.1 to about 1, where the aspect ratiois defined as the ratio of column-separation-cavity width to thecolumn-separation-cavity height dimensions (e.g., diameter/height—basedon a right-cylindrical-shaped separation cavity). In preferredembodiments, the chromatographic column can, for some applications, havean aspect ratio ranging from about 0.3 to about 1, and can also rangefrom about 0.5 to about 1. The actual dimensions for such columns arenot critical, but the separation cavity of a column can typically have ahydraulic radius ranging from about 0.1 cm to about 1 cm. Forright-handed cylindrical separation cavities, the diameter can rangefrom about 0.5 cm to about 3 cm, and the length can range from about 1cm to about 7 cm. Preferably, the columns can have diameters rangingfrom about 0.75 cm to about 2 cm and a length ranging from about 3 cm toabout 5 cm.

Reducing the column length while increasing the column width decreasesthe separation time required for a particular polymer sample. Withoutbeing bound by theory, employing relatively shorter columns results inshorter retention times at the same flow rate. Moreover, a reduction inlength and an increase in the column diameter results in reducedback-pressure, thereby allowing the use of higher mobile-phase flowratesbefore affecting the structural integrity of the solid-phase media. Alimitation to this approach for optimizing the column, however, is thedesired resolution of the detected property versus time—which can begiven by the number of theoretical plates per the column. Decreasedcolumn efficiency in high-speed separations may result in peakbroadening—thereby providing less detailed information on distributionof molecular weight (e.g., calculated using GPC calibration). However,the values of the peak-average molecular weights (M_(peak)) arerelatively unaffected. Reliable values of polydispersity can be thenobtained either by mathematical adjustment of data based on thechromatographic broadening of narrow molecular weight standards, ordirectly by using light-scattering detection. Despite such limitations,the achievable degree of separation of polymer components is,nonetheless, satisfactory for many polymer characterizationapplications—particularly for screening of combinatorial libraries ofpolymer components. Hence, such a relatively short and high-aspect ratiochromatographic column provides a further aspect for improving thesample throughput for a liquid chromatography system 10 or aflow-injection analysis system 20.

Chromatographic columns having the above-recited aspect ratios arepreferably combined with porous stationary-phase media suitable forgel-permeation chromatography. In one preferred method forcharacterizing a plurality of polymer samples, the samples are seriallyinjected into a mobile phase of a liquid chromatography system. At leastone sample component of the injected samples are separated from othersample components thereof in a chromatographic column having a porousmedia stationary-phase and an aspect ratio ranging from about 0.1 toabout 1. A property of at least one of the separated components of theplurality of samples is detected. When a plurality of samples are to becharacterized with such a column, the sample-throughput is preferably asrecited above.

Selection of a particular porous media to effect the separation can beguided by the particular sample components being separated. In general,the porous media stationary-phase employed in connection with suchmethod can have a relatively wide range of porosities, such as areobtained with typical “mixed bed” GPC stationary-phase media, andtypically expressed by a molecular weight exclusion limit ranging fromabout 20,000 to well over 10,000,000. Preferred “mixed-bed”stationary-phase media are PLGel Mixed-B and PLGel Mixed-C (PolymerLaboratories).

As an alternative to a single column having a stationary-phase porousmedia with a range of porosities, two or more of the relativelyhigh-aspect ratio columns can be employed with each column having a morenarrow range of porosities. In one such embodiment, for example, twohigh-aspect ratio columns are arranged in series in theliquid-chromatography mobile-phase flow path. One of the columns canhave a porous media with pore sizes of about 10³ Å—such pore size beingeffective for capturing relatively small molecules having a relativemolecular weight of up to about 20,000, while allowing molecules largerthan about 20,000 to pass through quickly. The other of the columns canhave a porous media with pore sizes of about 10⁵ Å—such pore size beingeffective for capturing and chromatographically separating moleculeshaving a relative molecular weight ranging from about 50,000 to about2×10⁶. As another example of such rapid size exclusion chromatography,one of the columns can have a porous media with pore sizes of about 10³Å with a second column having a porous media with pore sizes of about 30Å. (See Ex. 15). Such porous media can be obtained commercially fromPolymer Laboratories or Polymer Standard Service, among many others.

In other embodiments, however, the relatively high-aspect ratio columnscan be advantageously employed singly with porous stationary-phase mediahaving narrower, more focused porosity ranges. For example, the porousmedia can be selected to have a porosity selected to effectivelyseparate molecules having molecular weights ranging from about 10⁴ D toabout 10⁶ D. Such porous media can be obtained commercially from PolymerLaboratories or Polymer Standard Service, among others. Other narrowlytailored porosity ranges can also be employed with the relatively short,relatively wide column as discussed below in connection with targetedseparation.

In other variations, the short column may comprise columnstationary-phase packing other than is typically used for GPC, such asnormal-phase or reverse-phase silica particles, polymer monoliths,inorganic monoliths, and other well-known column stationary-phasematerials or filter media. For example, short columns containingadsorption chromatography stationary-phase can be used to removecomponents either more polar or less polar than the polymer sample ofinterest, such as water or solvents initially introduced with thesample. Also in a preferred aspect of this embodiment, more than oneshort column may be used in series, for example a short GPC column incombination with a short normal-phase adsorption chromatography column,such that polymer is separated from low-molecular-weight components,which are then further separated by polarity. (See Ex. 20). This can beparticularly useful for rapidly separating polymer from residual monomeror solvent in a polymerization reaction, and then further quantifyingthe type and amount of monomer or solvent within a single, rapidanalysis.

The detector employed in connection with a polymer characterizationmethod using the relatively high-aspect ratio column is not critical,and can generally include one or more of those detectors previouslydescribed. Preferably, a weight-average molecular weight can bedetermined from one or more detected properties. In preferredconfigurations, however, the high-aspect ratio geometry columns arecombined with the detector configurations described below in connectionwith rapid-fire light-scattering techniques.

When the liquid chromatography approach involves size exclusionchromatography, such approaches can be referred to as “rapid SEC”approaches. When the size-exclusion separation is effected as gelpermeation chromatography, the approaches can be referred to as “rapidGPC” approaches. Generally, optimized column designs for particularpolymer sizes of interest can increase the speed of separations ofpolymer samples (e.g., elution time) substantially compared to typicalGPC elution times, which typically require about 40 minutes to an hour.By combining the optimized column designs with the GPC beads, preferablyof a specific pore size as discussed below, elution times for polymersample separation can be reduced, in comparison to typical GPCseparations, on the order of 10 times, preferably 20 times and mostpreferably 40 times. Thus, if typical GPC elution times are in the rangeof 40 minutes, the elution times of the GPC separations of thisinvention are less than about 4 minutes, preferably less than about 2minutes and most preferably less than about 1 minute.

Targeted Separation

In many combinatorial research applications, a target polymer property(e.g., molecular-weight) is predefined. As such, thescreening/characterization method can be targeted for sensitivity to thepredefined target polymer property. For example, a screen may bedesigned to determine whether a polymer sample comprises a polymercomponent within a particular predetermined molecular weight range orparticle size range. In such cases, it may not be necessary to measure aprecise value for a sample if it outside of the predetermined range.

Such targeted separation protocols can be effectively employed with sizeexclusion chromatography such as gel permeation chromatography (GPC).Use of targeted-separation GPC techniques—with porosity of thestationary-phase media (e.g. beads) in the column being changed orvaried in comparison to standard GPC beads as described herein—ispreferably combined with an altered, optimized geometry of the GPCcolumn, again in comparison to standard GPC columns—such as therelatively-high aspect ratio column designs discussed above.

While some aspects of the following description refer to “beads”, suchreference is to be considered exemplary; other stationary-phase media(e.g., rods, monoliths, etc.) can be readily employed instead of suchbeads.

With respect to bead porosity, standard GPC columns use beads havingnominal pore sizes from several nm up to several hundreds of nm, capableof differentiating between dissolved polymer chains with effectivehydrodynamic radii (R_(h)) ranging from about 2 nm up to about 100 nm.Both the pore size of the beads and the effective R_(h) of the polymerchains is dependent on the chromatographic solvent used, as well asother factors such as temperature and/or ionic strength. In most commoncases, columns with mixed porosity beads are used to achieve linear GPCcalibrations, requiring a random distribution of differing pore sizesover a broad range of sizes. However, in such a case the resolvingability of the column for polymers with very close molecular weights islimited.

Therefore, one embodiment of this invention uses beads having porosityselected for rapid separation of polymer chains with a smaller range ofR_(h), corresponding to a particular molecular weight range, such as themolecular weight range targeted by the synthesis conditions used toprepare a combinatorial library. For polymers having molecular weightsin the range of 10⁴ to 10⁵ beads having porosity from 50 to 100 nm aretypically employed. For polymers having molecular weights in the rangeof 10³ to 10⁴ beads having porosity of 10-30 nm are usually employed.Conversely, for polymers having molecular weights in the range of 10⁵ to10⁶ beads having a porosity of several hundreds of nanometers areemployed. The precise pore sizes suitable for separation ofmacromolecules in certain range of the molecular weights depends also onthe structure and solvent interactions of both stationary-phase packingmaterials and polymer characterized.

Examples of useful porous beads of this invention include: Pl Gel fromPolymer Laboratories of various pore sizes; Suprema Gel 30 Å and 1000 Åfrom Polymer Standard Services (of 3 and 100 nm nominal pore size); andGM-Gel 3000 and 5000 from Kurita (of 380 and 540 nm nominal pore size).The composition of the beads is cross-linked polystyrene,poly(2,3-dihydroxypropyl methacrylate), and rigid polysacchariderespectively.

Use of the beads of appropriate porosity for separating polymers orparticles in particular size ranges allows the use of columns severaltimes shorter than for similar separation obtained using a typical setof conventional GPC columns (such as series of three 30 cm columns).Hence, the combination of targeted-separation stationary-phase mediawith optimized column geometry is a particularly-preferred embodiment ofthe invention.

One example of separation using the optimized column geometry andtargeted-separation techniques together involves the screening and/orcharacterization of emulsion polymer particles. Emulsion polymer samplescomprising polymer particles having a hydrodynamic radii up to about 200nm can be separated on a column packed with a macroporous rigid beadsvia size-exclusion. A property of the polymer samples can be detectedwith a mass detector (e.g., RI or ELSD/EMD). For such a separation, thecolumn preferably has a length of about 3.0 cm and a width of about 1.0cm, the stationary-phase porous media packing material has an effectivepore size of about 340 nm or 540 nm, and the flow-rate of the mobilephase can range from about 2 ml/min to about 10 ml/min. Effectiveparticle size separation and characterization, with reasonably goodquality, is obtained at a rate of about 50 seconds per sample.

Rapid-Fire Light Scattering

Methods involving short, high-aspect ratios columns, with targetedseparation medium and one or more light-scattering detectors arereferred to herein as “rapid-fire light-scattering” (RFLS) methods.

In one preferred RFLS method for characterizing a plurality of polymersamples, a polymer sample is injected into a mobile phase of a liquidchromatography system, and a low molecular-weight fraction of theinjected sample—comprising sample components having molecular weights ofnot more than about 1000—is separated from a high-molecular weightfraction thereof in a chromatographic column, The high molecular-weightfraction—comprising sample components having molecular weights of morethan about 1000 (including substantially all of the polymer component)is allowed to pass through the chromatographic column withoutsubstantial separation thereof. A property of the high molecular-weightfraction or of a component thereof is then detected. These steps arethen repeated for each of the plurality of polymer samples, in arapid-serial manner.

In this preferred method, the column preferably comprises a porousstationary-phase media having a range of pore sizes that facilitatepassage of the high-molecular weight fraction and separation of the lowmolecular-weight fraction from the high molecular-weight fraction.Moreover, the column preferably has a geometry such as that of therelatively high-aspect ratio columns described above. Specifically, thehigh-aspect ratio columns are preferably cylindrical with a length ofabout 1-5 cm and a width (diameter) of about 4 mm to about 1 cm. Thecolumn volume ranges from about 0.2 mL to about 4 mL. The flow rate, inthis preferred method, is typically faster than for normalchromatographic separation. Preferred mobile-phase flow rates are on theorder of 1-40 mL/min, and more preferably from about 1 ml/min to about25 ml/min. Faster flow rates, combined with relatively small volume ofthe system, results in a shorter residence time of the polymer sample inthe flow system, and therefore, a higher speed of characterization.Polymer properties can be determined for a plurality of samples at anaverage sample-throughput ranging from about 4 seconds to about 40seconds per sample. When a polymer sample is measured by this methodusing a differential refractive index detector and a static lightscattering detector, M_(w) values for multiple polymer samples can bedetermined at a rate that, compared to a minimum of about 20-40 minutesper sample using typical conventional GPC/light scattering techniques,represents an improvement in throughput of 30-600 times.

This preferred approach can effectively separate polymer components fromnon-polymeric components of the polymer sample. Hence, the low-molecularweight fraction can include many non-polymeric components, such as dustparticles and small molecules, such as solvent, residual catalyst and/orresidual monomer. Such separation can improve the accuracy of polymerproperty determinations, depending on the source and purity of thepolymer to be analyzed. In this aspect, this approach is particularlyuseful for screening a library of polymerization product mixtures from acombinatorial synthesis—where the polymer sample may comprise bothpolymeric and low-molecular weight components.

The detector configuration employed in connection with RFLS techniquesis not critical. Preferred configurations include, briefly: (1) a massdetector (e.g., RI detector, ELSD) combined with a SLS detector todetermine the weight-average molecular weight, M_(w), of the polymersample—preferably of a polymer solution; (2) a mass detector (e.g., a RIdetector, ELSD) combined with a SLS detector to determine particle of apolymer sample—preferably of a polymer dispersion or emulsion; (3) a DLSdetector (by itself) to determine the average particle size or a sizedistribution of a polymer sample—preferably of a polymer dispersion oremulsion, or alternatively, to determine an average molecular weight ora molecular weight distribution of a polymer sample—preferably of apolymer solution; (4) a SLS detector (by itself) at two or more angles(typically, but not necessarily 90° and 15° C.) to determine aweight-average molecular weight; and/or (5) SLS and DLS together todetermine the radius of gyration and the hydrodynamic radius, which canbe used to provide an indication of branching and higher-orderconformation and/or architecture. The high-aspect ratio column can alsobe employed with other detector configurations, including for example:(1) an RI detector (by itself) with samples of known concentration todetermine dn/dC—useful as an indicator for chemical composition; (2) aUV-VIS or photodiode array detector combined with a light scattering andmass detectors—for composition determinations; and/or (3) a viscometricdetector in combination with other detectors to provide additionaluseful information about the sample, such as polymer branching.

Precipitation-Redissolution Chromatography

Precipitation-redissolution chromatography involves the use of mobilephase having a solvent gradient in conjunction with an insolublestationary-phase (e.g., a polymer monolith). The polymer sample isinjected into a mobile-phase solvent that is a “poor” solvent for thepolymer being characterized (sometimes called a “non-solvent”), therebycausing precipitation of the polymer sample. The precipitated polymersample then adsorbs onto the stationary-phase (e.g., monolith) surface.Gradually, a better solvent for the polymer being characterized isintroduced into the mobile phase. When the better solvent contacts theprecipitated polymer sample, the smaller particles of the polymer sampleredissolve first. As more of the better solvent contacts theprecipitated polymer sample, larger particles of the polymer sampleredissolve, until the entire polymer sample has been redissolved. Inthis fashion, the polymer sample is separated by size (with the smallerparticles corresponding to smaller size molecules). Solvent choicesdepend on the solubility characteristics of the polymer samples beingcharacterized. For a typical hydrophobic polymer such as polystyrene,“good” solvents include tetrahydrofuran, toluene, dichloromethane, etc.,while “poor” non-solvents include methanol, ethanol, water, or hexane.It is generally preferred that the good solvent and the poor solventused for any particular separation be miscible.

The speed of separation of the precipitation-redissolutionchromatographic techniques depends on the gradient profiles (e.g., thetime rate of change of the mobile-phase composition—between solvent andnon-solvent). Typical pump systems supplied by HPLC equipmentmanufacturers have sufficient speed and accuracy such that the rate ofintroduction of the better solvent can be controlled to effectivelyelute the precipitated polymer sample in about 1 minute or less, and insome cases, less than about 45 seconds. Flow rates of the mobile phaseare preferably about 5 mL per minute and higher, up to the limit of thepump system used, which can be 20-40 mL per minute for commercial pumpswith large-volume pump heads.

Since polymer solubility is also a function of temperature, temperaturegradients can also be employed, individually or in combination with themobile-phase compositional (e.g., solvent) gradient. While thistechnique is discussed in greater detail below in connection withhigh-temperature liquid chromatography, the temperature-gradienttechnique can also have applications at relatively low temperatures—nearambient or below, depending on the particular polymer samples beingcharacterized. Briefly, the sample is introduced at a lower temperature,enhancing precipitation of the polymer, and then the temperature isincreased (optionally in conjunction with a change in composition of themobile phase to a good solvent) to allow selective dissolution andelution of retained polymer.

The precipitation-redissolution chromatography approaches describedherein—particularly employing monolithic columns such as those disclosedby Petro et al., vide supra., generally lead to high-speedcharacterization with good quality of information.

Adsorption Chromatography

Adsorption chromatography using solvents selected for particularpolymers or polymer libraries is an alternative method of this inventionfor rapidly separating polymer samples. In this technique, the polymersample is reversibly adsorbed from the mobile phase onto thestationary-phase of the column. Adsorption can be enhanced by solventselection such that the polymer samples have decreased solvency in thechosen “weaker” solvent, as compared to a “stronger” solvent thatcompletely dissolves the polymer samples. As such, the adsorption and/orsubsequent desorption can be faster.

The solid-phase media can be selected according to the type of polymerto be analyzed. Exemplary solid-phase media for this approach includeporous monoliths and beads. Silica or hydrophilic polymer beads are usedfor adsorption of polar polymers or for removing of highly polarcomponents of the samples, such as water, which would otherwiseinterfere with the analysis of compounds of interest, such as monomersand polymers. Polymeric beads with diol functionalities are preferredfor this purpose since they have higher adsorptivity than silica withminimized non-specific interactions with the characterized polymers (SeeM. Petro, et al., Anal. Chem., 1997, 69 3131; M. Petro, et al., J.Polym. Sci. A: Polym. Chem., 1997, 35, 1173; J. M. J. Fréchet, et. al.,Polym. Mater. Sci. Eng. 1997, 77, 38.).

The typical mobile phase (e.g., solvent) used for this adsorptionchromatography is tetrahydrofuran, either alone or in mixtures withhexane (to enhance adsorption) or water (to enhance elution).Octadecyl-silica beads (commonly used in conventional reverse-phaseHPLC) and polystyrene-based monoliths are used for a separation ofcompounds of medium polarity under the conditions typical ofreversed-phase chromatography, usually in combination with a mixture ofwater and tetrahydrofuran. Optionally, gradients in connection with thistechnique can be employed, changing either the composition, temperatureor flow rate of the mobile phase.

Overlaid Injection/Low-MW Insensitive Detection

Another preferred approach for characterizing a plurality of polymersamples takes advantage of the fact that chromatographic separation istypically a rate-limiting step for liquid chromatographycharacterization systems. According to this approach, the effectiveseparation time is reduced by serially overlapping samples. Since agiven sample is being processed closer in time to the preceding and thesuccessive sample, the overall sample-throughput is improved.

More specifically, a plurality of polymer samples can be characterizedby injecting a first polymer sample into a mobile phase of a liquidchromatography system, separating at least one sample component of theinjected first sample from other sample components thereof in achromatographic column, and detecting at least one property of theseparated sample component of the first sample. The second polymersample is then injected into the mobile phase of the liquidchromatography system at a particuarly-controlled time, referred to forpurposes herein as the successive-sample injection time, t_(LCI2). Atleast one sample component of the injected second sample is separatedfrom other sample components thereof, and at least one property of theseparated sample component of the second sample is detected. The cycleis repeated for each pair of preceding/successive polymer samples in theplurality of polymer samples. In preferred applications, at least 8different polymer samples are characterized according to the method.

The successive-sample injection time, t_(LCI2), is an important factorin connection with this approach. In general, the particular degree ofoverlap between successive samples can vary, depending on the desiredthroughput and information quality. Preferably, the second polymersample is injected into the mobile phase of the liquid chromatographysystem at an injection time that provides an average sample-throughputof not more than about 10 minutes per sample for the plurality ofsamples.

In one approach, the second polymer sample can be injected whiledetecting at least one property of the separated sample component of thefirst sample. In another approach, effectively providing a somewhatgreater degree of overlap, the second polymer sample can be injectedwhile separating at least one sample component of the injected firstsample from other sample components thereof. In a further approach,providing even a greater degree of overlap, the second polymer samplecan be injected while advancing the injected first sample to thechromatographic column.

Viewed from another aspect, the second polymer sample can be injectedsuch that the trailing edge of a detection profile for the first sampleoverlaps with the leading edge of a detection profile for the secondsample. That is, the serial injection of polymer samples into the mobilephase can be at a rate that compresses the allowed cycle time so muchthat the sample components from a first sample and sample componentsfrom a successive second sample reside in the detection cavity of thedetector simultaneously. In GPC applications, for example, in whichstationary-phase is a porous media, the later-eluting smaller-moleculecomponents of the first sample can be present in the detection cavity ofthe detector at the same time as the earlier-eluting, larger-moleculecomponents of the second sample. An analogous effect can be realizedwith other chromatographic separation approaches, such asprecipitation-redissolution chromatography or adsorption chromatographyor reverse-phase chromatography.

In flow-injection analysis approaches, the overlaid samples can becompressed even further. For example, the compression can be such thatthe samples have overlapped leading and trailing portions or regions,with only a small volume (e.g., sufficient for detection purposes) ofpure, non-overlapped sample, available for detection in a detectioncavity.

In such overlapped cases, and in particular those cases in whichcomponents from a preceding and a successive polymer sample reside inthe same detection cavity at the same time, it is advantageous to employa detector that is insensitive to the sample components from one of thesamples. For example, in the exemplary case based on GPC, it isadvantageous to employ a detector that is insensitive to samplecomponents having low molecular weights—corresponding to thelater-eluting sample components of the first (preceding) polymer sample.Preferably, a detector is employed that is insensitive to samplecomponents having a weight-average molecular weight of less than about1000. The detector can, most preferably, be an evaporativelight-scattering detector (ELSD).

The overlaid-injection approach described herein allows for substantialimprovements in sample throughput. For example, complete molecularweight information (including PDI) and composition for a plurality ofsamples can be obtained—with a level of quality comparable toconventional GPC—using an “accelerated size exclusion chromatography”approach that incorporates this technique. (See Ex. 17 and Ex. 18). Thisapproach is suitable for determining a characterizing property ofinterest, evaluating monomodality versus polymodality, and evaluatingpurity with a sample throughput of not more than about 8 minutes persample. In another application of the overlaid-injection approach,average molecular weights and molecular weight distribution informationcan be obtained—with a level of quality that is reasonably good—using a“rapid size exclusion chromatography with enhanced resolution” approach.(See Ex. 16).

Preferred Flow-Injection Analysis Protocols

A plurality of polymer samples are characterized according to thepresent invention with a flow-injection analysis system by seriallyinjecting a plurality of polymer samples into a mobile phase of acontinuous-flow detector, and detecting a property of the injectedsamples or of components thereof with the continuous-flowdetector—preferably at an average sample-throughput of not more thanabout 10 minutes per sample. In some embodiments, two or morecontinuous-flow detectors are used in series. The combination of two ormore detectors allows for the determination of certain polymerattributes of interest. Because no substantial chromatographicseparation of the polymeric components of the sample occurs,flow-injection analysis allows for measurement of properties of aheterogeneous polymer sample, such as average properties (e.g., averagecomposition or average molecular weight) or, with some detectors (e.g.,dynamic light-scattering detectors) specific component properties. Thisembodiment may be particularly rapid, limited only by the speed of thesampling or by the residence time of the liquid in the flow system. Thisembodiment is particularly useful for rapid screening of combinatorialpolymerization reactions, especially to determine polymerizationconditions or characteristics.

In a preferred approach, a plurality of polymer samples arecharacterized with a flow-injection analysis system as follows. A firstpolymer sample is withdrawn from a first sample container, preferablyinto a probe of an auto-sampler. At a first injection time, t_(FII1), atleast a portion of the withdrawn first sample is injected into themobile phase of the continuous-flow detector, and advanced toward adetection-cavity of a detector—without substantial chromatographicseparation thereof. A property of the injected first sample or of acomponent thereof is detected while the sample resides in the detectioncavity of the detector. A second polymer sample is withdrawn from asecond sample container. At a second injection time, t_(FII2), at leasta portion of the withdrawn second sample is injected into the mobilephase of the continuous-flow detector. A property of the injected secondsample is detected.

In general, the steps of withdrawing the polymer samples, injecting atleast a portion of the withdrawn polymer samples into the mobile phaseof a flow-through detector, advancing the injected samples toward thedetection cavity of the detector, and detecting a property of theinjected samples are controlled such that the flow-injection cycle time,T_(FI), delineated by the difference in time, t_(FII2)−t_(FII1), is notmore than about 10 minutes. Hence, the speed of detection is limited, ina practical sense, by sampling rates, mobile phase flow rate in theflow-injection analysis system, and required sample residence time inthe continuous-flow detector. In preferred embodiments, theflow-injection cycle time is not more than about 8 minutes, andpreferably less than 4 minutes, less than 2 minutes, less than 1 minuteor less than 30 seconds. Flow-injection cycle times of less than 20seconds, and less than 10 seconds can also be achieved.

FIGS. 7A and 7B show a preferred configuration for a flow-injectionanalysis system 20. An auto-sampler 200 (described in connection withFIG. 4) withdraws a sample 20 from a sample container 202 into aninjection probe 201. A mobile phase is supplied to the system 20 fromreservoir 114 via pump 116. The polymer sample 20 is injected into themobile phase—either directly (not shown) or indirectly via loading port204, and is advanced through sample transfer line 206 to valve 210.Valve 210 is preferably an injection valve 100 having an injection port108. After optionally passing through in-line filter 212, the sample isdetected in one or more continuous-flow detectors 216, 218 (e.g., alight-scattering detector and/or a concentration detector). Optionally,the flow-injection system can be used as a rapid liquid-chromatographysystem by including a high-aspect ratio column 214. The valve 210,filter 212, column 214 (if included) and detectors 206, 218 canoptionally be housed within a temperature-controlled environment (e.g.,oven 208). The sample is discharged to a waste container 140.

A single microprocessor (e.g., computer 222) (FIG. 7A) can control theentire system 20—including sampling with the auto-sampler 200, injectingof samples into the mobile phase via loading port 204, mobile-phasefluid flow via pump 116, and receiving and processing the data from thedetectors 216, 218. In an alternative configuration shown in FIG. 7B,the system 20 can be controlled with two microprocessors (e.g.,computers 350, 352)—enabling high-throughput rapid-serial detection. Therobotic auto-sampler 200 and data acquisition from detectors 216, 218can be controlled with the two different computers 350, 252 synchronizedvia a trigger pulse. More specifically, computer 352 can control therobotic auto-sampler 200, mobile-phase pump 116, and injection valve210. A serial port on the computer 352 can be connected to a valvecontroller 360, which in turn can be connected to the injection valve210. The valve controller 360 can also be connected to a pulse wideningcircuit 362 via a digital logic circuit (using a pulsed contactclosure). The valve controller 360 can also allow for manual (e.g., pushbutton) operation of the valve 210, using the same digital logiccircuit. The pulse widening circuit 362 can be connected to a dataacquisition module 364 standard for chromatographic analysis. The dataacquisition module 364 can be connected to the second computer 350. Inoperation, the valve controller 360 sends a pulse signal to the dataacquisition module 364 indicating that a sample has been injected in tothe system 20, causing computer 350 to begin acquiring data from, forexample, a lighting-scattering detector 216 and a refractive-indexdetector 218 via the data acquisition module 364. The computer 352 caninclude a time variable appropriate for the characterization methodbeing employed to space the injection of samples according apredetermined interval. If a new injection pulse is sent from computer352, computer 350 can initiate new acquisition of data for the nextsample and discontinues data acquisition for the existing sample. Asimilar control configuration can be effected for liquid chromatographysystems.

The following protocols can be effectively applied individually, or incombination, and moreover, can find applications with low-, ambient-, orhigh-temperature characterization protocols. Although such protocols areprimarily described with respect to polymer samples, and although suchpolymer samples are preferred samples for the flow-injection analysisprotocols disclosed herein, non-polymer samples can also be employed insome applications (e.g., pigment characterization, etc.).

Flow-Injection Light-Scattering

Light-scattering detectors (SLS, DLS, ELSD) can be advantageouslyapplied in flow-injection analysis applications—alone or in combinationwith other light-scattering detectors or other, non-light-scatteringdetectors. High-throughput flow-characterization methods using at leastone light-scattering technique can be referred to as “flow-injectionlight-scattering” (“FILS”).

A number of flow-injection light-scattering approaches have beendeveloped for rapidly screening polymer samples without chromatographicseparation thereof. Each of the approaches can be employed to determinepolymer properties that include average molecular weight of polymersamples (e.g., dissolved polymer samples) or average particle sizes ofpolymer samples (e.g., emulsified or dispersed polymer samples), as wellas non-averaged properties of interest. In a first method, a massdetector, such as an RI detector or an ELSD, is combined with a SLSdetector to determine the weight-average molecular weight, M_(w), of thepolymer sample—preferably of a polymer solution. In a second method, amass detector (e.g., a RI detector or an ELSD) is combined with a SLSdetector to determine particle size (e.g., volume-averaged particlediameter) of a polymer sample—preferably of a polymer dispersion oremulsion. In a third approach, a DLS detector can be used by itself todetermine an average particle size or a size distribution of a polymersample—preferably of a polymer dispersion or emulsion, or alternatively,to determine a weight-average molecular weight or a molecular weightdistribution (shape and estimate of PDI) of a polymer sample—preferablyof a polymer solution. According to a fourth approach, a SLS detectorcan be used by itself at two or more angles (typically, but notnecessarily 90° and 15° C.) to determine the radius of gyration. In yetanother approach, a SLS and DLS can be employed together to determinethe radius of gyration and the hydrodynamic radius, which can be used toprovide an indication of branching and higher-order conformation and/orarchitecture.

Some flow-injection embodiments employ other detectors—withoutlight-scattering detectors. For example, in one method, dn/dC—therelationship of refractive index and concentration of the polymersample—can be determined without chromatographic separation of polymercomponents, by measuring the response of a RI detector for samples ofknown concentration. This relationship can be effectively used, forexample, as an indicator of chemical composition of the polymer.Alternatively, in a FILS technique, more detailed information about thechemical composition of analytes can be obtained using UV-VIS orphotodiode array detector in a series with the light scattering and massdetectors. Inclusion of a viscometric detector can provide additionaluseful information about the sample, such as polymer branching.

Generally, FILS allows for the detection of both homogeneous andheterogeneous samples. FILS is optionally, and generally preferably,combined with sample pretreatment as discussed, including for example,various on-line pretreatment techniques such non-chromatographicseparation techniques with filters.

As noted above, the detector configurations employed with theabove-discussed FILS techniques can, in preferred embodiments, beadvantageously employed in combination with a very quick chromatographicseparations using the relatively high-aspect ratio column geometriesand/or targeted-separation approaches described above. Quickchromatographic separation for macromolecule or particle size separationor for separating high-molecular weight (large) particles or moleculesfrom low-molecular weight (small compounds) are preferred in combinationwith the FILS detector configurations. The speed of characterizationmethods of the invention that use capillaries, columns, and cartridgesof low volumes of 0.1-1 mL and high flow rates upwards of 20 mL/min canbe less than 10 seconds per sample, or less than 5 seconds per sample,and approach 1-3 seconds per sample.

The nature of the polymer samples and analysis technique will influencewhether a short column, filter, or pulse damper is employed. Forexample, an array of solutions comprising pure polymers with nosignificant presence of large particulates or small molecules can berapidly characterized for M_(w) by the FILS methods of this invention,using an RI and SLS detector, without a chromatographic column and insome cases, also without a filter.

FILS can also be combined with variable-flow injection analysistechniques (discussed below) with or without separation or otherpretreatment.

Variable Flow Light-Scattering

In another preferred approach, the flow-rate of the mobile phase iscontrolled such that an injected polymer sample is rapidly advanced toand/or rapidly passed away from the detection cavity of a flow-throughdetector, and such that the polymer sample is slowed or stopped whilethe sample resides in the detection cavity of a light-scatteringdetector. In such variable-flow (also referred to as “stop-and-go”)techniques, the polymer sample remains slowed or stopped during a periodof time sufficient for detection/characterization. This approach canhave a significant impact on the injection-to-detection run time for asingle polymer sample, and the effect is particularly substantial forcharacterizing a plurality of samples.

When the variable-flow light-scattering protocols are applied to aplurality of polymer samples, such as a library of polymer samples, theaverage sample-throughput can be greatly improved over constant-flowlight-scattering systems. More particularly, a plurality of polymersamples can be characterized by serially injecting a plurality ofpolymer samples into a mobile phase of a continuous-flowlight-scattering detector, advancing the injected samples toward adetection cavity of the detector, detecting light scattered from theinjected samples or from a component thereof in the detection cavity,flushing the samples from the detection cavity after detecting thescattered light, passing the flushed sample away from the detectioncavity, and controlling the flow-rates of the samples during the stepsof injecting, advancing, detecting, flushing and/or passing such thatthe average sample throughput is not more than about 10 minutes persample, preferably not more than about 4 minutes per sample, morepreferably not more than about 2 minutes per sample, and most preferablynot more than about 1 minute per sample. In some applications, theaverage sample throughput can be preferably not more than about 50seconds per sample, more preferably not more than about 40 seconds persample, even more preferably not more than about 30 seconds per sample,more preferably yet less than about 20 seconds per sample and mostpreferably less than about 10 seconds per sample.

Although the flow of the mobile phase can be temporarily stoppedaccording to one or more variations of this method, the methods, and theflow-injection systems and detectors employed are considered,nonetheless, to be continuous-flow systems and detectors. Moreover,while this variable-flow light-scattering detection approach has primaryapplications with respect to a flow-injection analysis system, ananalogous approach can be applied in connection withliquid-chromatography systems, with accommodations made, for example,for maintaining an appropriate, typically constant flow-rate through thechromatographic column.

According to one variation of the method, a polymer sample is rapidlyadvanced to the detection cavity of a light-scattering detector, andthen slowed or stopped for detection therein. Such a variation will bereferred to herein as a rapid-advance, slow-detect approach. Morespecifically, a polymer sample can be characterized by injecting apolymer sample into a mobile phase of a continuous-flow light-scatteringdetector, and advancing the injected sample is advanced toward adetection cavity of a light-scattering detector. The sample-containingmobile phase has a advancing flowrate, V_(ADVANCE), while the injectedsample is advanced toward the detection cavity. The flowrate of thesample-containing mobile phase is subsequently reduced to a relativelylower detection flowrate, V_(DETECT). The light scattered from theinjected sample or from a component thereof is detected in the detectioncavity of the detector while the mobile-phase flowrate is reduced to thedetection flowrate, V_(DETECT). The sample is then flushed from thedetection cavity after the scattered light is detected.

Following detection, the polymer sample can be passed away from thedetection-cavity at the same slower detection rate or, alternatively andpreferably, at an increased rate. That is, the rapid-advance,slow-detect approach can be followed by either a slow-pass, or arapid-pass approach. Preferably, the overall approach is arapid-advance, slow-detect, rapid-pass approach. More specifically, theflowrate of the sample-containing mobile phase is increased to a passingflowrate, V_(PASS), after detecting the scattered light, and the flushedsample is passed away from the detection cavity of the light-scatteringdetector at the passing flowrate, V_(PASS). Preferably, the passingflowrate, V_(PASS), can be substantially the same as the advancingflowrate, V_(ADVANCE) (accounting for normal variations in flow-controlcapabilities).

In an alternative variation of the method, an injected polymer sample isdetected in a detection cavity of a light-scattering detector at arelatively slow flow-rate (or while stopped), and then rapidly passedaway from the detection cavity. Such a slow-detect, rapid-pass variationis more specifically described as follows. A polymer sample ischaracterized by injecting the polymer sample into a mobile phase of acontinuous-flow light-scattering detector. Light scattered from theinjected sample or from a component thereof is detected in a detectioncavity of the detector. The sample-containing mobile phase has adetection flowrate, V_(DETECT), while the scattered light is detected.The sample is flushed from the detection cavity after detecting thescattered light. The flowrate of the sample-containing mobile phase isincreased to a higher passing flowrate, V_(PASS), after detecting thescattered light, and the flushed sample is passed away from thedetection cavity of the detector at the increased higher passingflowrate, V_(PASS). The flow-rate of the mobile phase while the sampleis being advanced can be relatively slow, or fast, such that the overallapproach is slow-advance, slow-detect, rapid-pass, or rapid-advance,slow-detect, rapid-pass.

Hence, in a most preferred approach, a plurality of polymer samples arecharacterized by withdrawing a polymer sample from a sample container.The withdrawn polymer sample is injected into a mobile phase of acontinuous-flow light-scattering detector while the mobile phase has aadvancing flowrate, V_(ADVANCE). The injected first sample is advancedtoward a detection cavity of the detector while maintaining the flowrateof the mobile phase at the advancing flowrate, V_(ADVANCE). The flowrateof the mobile phase is then reduced to a detection flowrate, V_(DETECT).Light scattered from sample or from a component thereof is detected inthe detection cavity of the detector while the mobile phase flowrate isat the reduced detection flowrate, V_(DETECT). The first sample isflushed from the detection cavity after detecting the scattered light,and the flowrate of the mobile phase is increased to the advancingflowrate, V_(ADVANCE), after detecting the scattered light. The flushedsample is passed away from the detection cavity of the detector whilemaintaining the flowrate of the mobile phase at the advancing flowrate,V_(ADVANCE). The aforementioned steps can then be repeated for aplurality of polymer samples

For any of the above protocols, when a plurality of polymer samples arebeing characterized with a variable-flow light-scattering approach, thetiming of injection of a successive (e.g., second) polymer sample canvary relative to the position of the preceding (e.g., first) polymersample. More specifically, a second polymer (successive) sample can beinjected into the mobile phase of the continuous-flow light-scatteringdetector at various times after the first (preceding) sample has beeninjected. In one variation, the second polymer sample is injected whilethe first polymer sample is being passed away from the detection cavityof the light-scattering detector. In another variation, the secondpolymer sample is injected while the light scattered from the firstpolymer sample is detected (that is, while the first polymer sampleresides in the detection cavity). In yet a different variation, thesecond polymer sample is injected while the first polymer sample isadvanced toward the detection cavity of the light-scattering detector.The preferred approach with respect to the timing of the injection of asecond, successive sample in a plurality of polymer samples canvary—particularly depending on the sample size, the sustainable samplingthroughput, and the actual flow-rates of the mobile phase—for advancingflow-rates, detection flow-rates, passing flowrates, and/or higherflowrates.

The polymer sample is not narrowly critical and can, in general, be apolymer sample as described above. Preferred applications of thevariable-flow light-scattering detection protocol include polymersamples comprising a polymer component having a particle that hasdiffusional mobility in the system mobile phase. Typical particle sizes(diameters) range, in typical mobile-phase solvents, from about 1 nm toabout 500 nm and preferably from about 5 nm to about 300 nm. Theseranges of particle size could be extended by changing the viscosity ofthe mobile phase, for DLS-detected systems, since DLS measuresdiffusion. The concentration of the polymer sample can generally be thesame as described above, except that the lower limits may be extended toas low as detectably possible—sufficient to scatter a light signal.

The ratio of flow-rates and the actual flow-rates employed in connectionwith any variation of this approach are not critical. In general,however, advancing flowrate, V_(ADVANCE), is greater than the detectionflowrate, V_(DETECT), by a factor of at least about two, more preferablyby a factor of at least about five, and even more preferably by a factorof at least about ten. The advancing flowrate, V_(ADVANCE), can range,for example, from about 1 ml/min to about 25 ml/min, preferably fromabout 1 ml/min to about 10 ml/min, more preferably from about 1 ml/minto about 5 ml/min and even more preferably, from about 1 ml to about 3ml. The first flowrate is most preferably about 1.5 ml/min. Thedetection flowrate, V_(DETECT), can range from about zero to about 1ml/min, and preferably ranges from about 0.1 ml/min to about 0.5 ml/min,and more preferably, from about 0.1 ml/min to about 0.3 ml/min.

The continuous-flow light-scattering detector can be astatic-light-scattering (SLS) detector or a dynamic-light-scattering DLSdetector. In preferred embodiments, both a SLS detector and a DLSdetector can be employed, with the SLS being used primarily forflow-control purposes, and the DLS detector data being used fordetermining a characterization property of interest (e.g.,weight-average molecular weight, particle size distribution, molecularweight distribution or other property derivable from the distribution ofthe diffusion constant). For flow-injection analysis systems having aDLS detector, the detection flowrate is preferably a constant flowrateduring the period of time when the polymer sample or a component thereofis detected. For systems having a DLS detector or a SLS detector, theflow through the detection cavity is preferably non-turbulent.

Control of the flowrates can be effected by a number of differentcontrol schemes. According to one control approach, the advancingflowrate, V_(ADVANCE), is reduced to the detection flowrate, V_(DETECT),when a leading edge of the polymer sample enters the detection cavity ofthe light-scattering detector. The detection flowrate, V_(DETECT), isthen maintained for a detecting period of time ranging from about 1second to about 60 seconds or for a period of time ranging from about 3seconds to about 40 seconds. The detecting period more preferably rangesfrom about 5 seconds to about 20 seconds, even more preferably fromabout 7 seconds to about 15 seconds, and most preferably from about 10seconds to about 12 seconds. As noted, the leading edge can be detectedwith a static-light scattering detector or a dynamic light-scatteringdetector signal that causes a change in a detector output signal (e.g.,scattered-light intensity, voltage), thereby indicating the presence ofthe polymer sample in the detection cavity. The leading edge can also bedetected with other detectors, such as an ELSD, or RI detector. Theaforedescribed control approach is represented schematically in FIG. 7D.(See also Ex. 24). In an alternative control scheme, the timing forlowering the flowrate from the advancing flowrate to the lower detectionflowrate can be based entirely on system mechanics: primarily flow-ratesand residence times in the flow path. The detecting period is preferablysufficient to obtain scientifically meaningful data. The flush-outperiod can be a predetermined period (e.g., from about 5 seconds toabout 10 seconds) or can be controlled based on detector output,results, etc.

In one configuration, a continuous-flow light-scattering detectionsystem for effecting the variable-flow light-scattering protocolscomprises, with reference to FIG. 2B, an injection valve 100 having aninjection port 108, optionally a loading port 204 (FIG. 7) in fluidcommunication with the injection port 108 via a transfer line 206 (FIG.7), for injecting a sample into the mobile phase. The system 20 alsocomprises a light-scattering detector 130 having a detection cavity 131.The detection cavity 131 has an inlet port and an outlet port throughwhich a sample-containing mobile phase can flow. A mobile-phase fluidsource (e.g., reservoir 114) is in fluid communication with the inletport of the detection cavity, and a pump 116 provides the motive forcefor flow of the mobile phase from the source to the detection cavity130. The system 20 further comprises, a detector (not shown) forindicating the position of an injected sample relative to the detectioncavity, and a flow-control element (not shown) for controlling theflowrate of the mobile phase. A flow-controller is preferably incommunication with the detector and with the flow-control element. Flowcan be initiated by a pump or by the auto-sampler, optionally using aninjection valve 100 (valve 210) similar to that described above in FIG.3. In the embodiments that use a pump, the pump would be connected tothe valve at the inlet port 101. If no pump is used, the inlet port 101is plugged and the liquid medium is provided by the sampler through theloading port 204, preferably with volume control of the injected sample.

High-Temperature Characterization

A number of commercially important polymers are preferably characterizedat temperatures above room temperature. For example, polymers that areinsoluble at room temperatures, but soluble at higher temperatures in aparticular solvent, can be conveniently characterized at such highertemperatures. Exemplary polymers that can be characterized attemperatures above about 75° C. include aqueous-associated orphysically-gelling polymers (e.g., gelatin, polyvinyl alcohols). Somepolymers are preferably characterized at even higher temperatures—aboveabout 125° C., including for example, polyethylene (typically about 130°C.), polypropylene (typically about 150° C.) and polyphenylenesulfide(typically about 200° C.).

Accordingly, a number of methods, systems and devices have beendeveloped to effect high-temperature characterization of single polymersamples and/or of a plurality of polymer samples. As used herein, theterm “high-temperature characterization” refers to characterization of apolymer sample at temperatures that are above about 75° C. and typicallyranging from about 75° C. to about 225° C., or highertemperatures—limited by the integrity of the separation medium andmobile phase at such higher temperatures. For manycommercially-important polymers, high-temperature characterization canbe effected at temperatures ranging from about 100° C. to about 200° C.,or from about 125° C. to about 175° C. Methods, systems and devices arediscussed below that relate to improved aspects of polymer sampling,chromatographic separation and detection for high-temperaturecharacterization. Those methods, systems and devices that are directedto polymer sampling or detection will have applications for flowcharacterization systems generally (i.e., for both liquid chromatographysystems and flow-injection analysis). Moreover, while the approachesdiscussed below are advantageous in connection with high-temperaturecharacterization, some of the approaches have applications outside ofhigh-temperature characterization, and, therefore, should not becategorically limited to high-temperature applications unlessspecifically required by the claims. Likewise, while some of theapproaches are described in connection with characterizing a singlepolymer, they can be and for many applications are preferably, likewiseapplicable to characterizing a plurality of polymer samples.

Auto-Sampling with an External, Heated Injection Probe

Automated sampling of polymer samples for high-temperaturecharacterization is preferably effected with an auto-sampler having aheated injection probe (tip). With reference to FIG. 4 and to FIGS. 5Athrough 5C, such an auto-sampler can comprise a probe 201 mounted on asupport arm 203, a microprocessor 222 for controlling three-dimensionalmotion of the probe between various spatial addresses, and a pump (notshown) for withdrawing a polymer sample into the probe. The probe 201has a surface defining a sample-cavity 2014 and a sampling port 2016 forfluid communication between the sample cavity 2014 and a polymer sample20. The probe also preferably comprises a solvent port 2015 for fluidcommunication between a solvent supply reservoir and line (not shown)and the sample cavity 2014. The probe 201 is adapted for fluidcommunication with an injection port 108 or a loading port 204 of acontinuous-flow polymer characterization system.

Significantly, the auto-sampler further comprises a temperature-controlelement 211 in thermal communication with the auto-sampler probe 201 formaintaining a drawn polymer sample residing in the probe at apredetermined temperature or within a predetermined range oftemperatures—preferably a temperature of not less than about 75° C., orif necessary, not less than about 100° C. or not less than about 125° C.The temperature-control element 211 can be, in the general case, aheating element or a cooling element (for low-temperaturecharacterizations). The particular design of the heating element orcooling element is not critical. With reference to FIGS. 5A through 5B,the heating element 211 can be, for example, a resistive-heating elementsuch as a resistive wire 213 in adjacent proximity to the sample cavity2014 of the probe 201 (FIG. 5A). The heating element 211 canalternatively be a fluid-type heat-exchanger heating element having afluid-containing tubular coil 215 around the probe 201 (FIG. 5B). In anycase, the temperature-controlled probe 201 can have a body 2012 encasingthe heating element 211, and preferably a thermocouple 2018 fortemperature monitoring and control. In another alternative embodiment,with reference to FIG. 5C, the heating element 211 can be the body 2012of the probe itself, where the body 2012 comprises a large thermal mass,preferably surrounded by an insulator 2020. The large-thermal-mass body2012 can be heated (or in the general case, cooled) by periodicallyallowing the body to thermally equilibrate with a hot environment suchas a surface or fluid via conduction, convection or thermal radiation(or generally, with an cold environment).

Advantageously, such a heated probe can maintain the sample at therequired temperature while the sample resides in the sample-cavity ofthe probe. As such, unlike conventional high-temperaturecharacterization systems, the auto-sampler probe, as well as associatedrobotic support arm, can be located external to (outside of) a heatedenvironment (e.g., oven).

Hence, referring to FIG. 6, a polymer sample 20 can be characterized bywithdrawing a polymer sample from a sample container into a heatedauto-sampler injection probe 201. The heated probe 201 and, typically,the sample container (e.g., a library of polymer samples 106) areresident in a first environment maintained at about ambienttemperature—external to a heated second environment (e.g., oven 112)maintained at a temperature of not less than about 75° C., in whichother components (e.g., chromatographic column 102) of thechromatographic system 10 reside. The polymer sample 20 is maintained,generally, at a temperature of not less than about 75° C. during aperiod of time including from when the sample is withdrawn from thesample container to when the sample is within the heated secondenvironment. In some applications, such as for flow-injection analysis,the sample is preferably maintained at a temperature of not less thanabout 75° C. during a period of time including from when the sample iswithdrawn from the sample container to when the property of the sampleor of a component thereof is detected. More specifically, the samplecontainer, if external to the second heated environment, is preferablyheated to maintain the polymer sample at a temperature of not less thanabout 75° C. while the sample is resident in the container. Theinjection probe is likewise heated to maintain the withdrawn sample at atemperature of not less than about 75° C. while the sample is residentin the probe 201. A preparation station comprising one or morepreparation containers can also be heated to the requiredhigh-temperatures.

At least a portion of the withdrawn, high-temperature sample is loadedinto an injection port 108 of a flow characterization system (e.g., aliquid chromatography system or a flow-injection analysis system),either directly or through a loading port 204 and a transfer line 206.The injection port is adaptable for fluid communication with adownstream elements (e.g., chromatographic column 102 and/orcontinuous-flow detector 230), and can reside internal to or external tothe heated second environment. If the injection port resides external tothe heated second environment—in the first, near-ambient environment—theinjected sample is preferably advanced (e.g., toward the chromatographiccolumn) through a transfer line providing fluid communication betweenthe injection port and the chromatographic column and/or detector 230while heating the transfer line to maintain the injected sample at atemperature of not less than about 75° C. while resident in the transferline. In a preferred sample loading configuration, a sample can beloaded with an external auto-sampler 104′ by inserting the probe 201 ofthe auto-sampler 104′ through an aperture 113 in the heated-environmentenclosure (e.g., oven 112) and into a loading port 204 within the heatedenvironment. In such a configuration, the probe 201 can be sufficientlylong to reach into the loading port 204 within the heated environment.The loaded sample is, in any case, injected into a mobile phase of theflow characterization system. If the flow characterization system is aliquid chromatography system 10, the sample is chromatographicallyseparated. If the flow characterization system is a flow-injectionanalysis system, the sample is optionally filtered. In any case, aproperty of the sample or of a component thereof is then detected withone or more detectors 130, 132.

For polymer samples being characterized at even higher temperatures, theinjection probe can be heated to maintain the withdrawn sample at atemperature of not less than about 100° C., or if necessary, not lessthan about 125° C., while resident in the injection probe. The heatedsecond environment can be maintained at a temperature of not less thanabout 100° C., or, if necessary, not less than about 125° C. The sampleis, in such cases, respectively maintained at a temperature of not lessthan about 100° C., or if necessary, not less than about 125° C., duringthe period of time including from when the sample is withdrawn from thesample container to when the sample is injected into the portion of theflow characterization system (e.g., liquid chromatography system)residing in the heated second environment.

Rapidly Heated/Cooled Column and System

According to another high-temperature characterization protocol, apolymer sample can be characterized in a liquid chromatography systemthat is readily adapted to high-temperature characterization protocols.Specifically, a chromatographic column is prepared for separation byheating the column from about ambient temperature to about 75° C. inless than about 1 hour. A polymer sample is injected into the mobilephase of the liquid chromatography system and loaded onto the heatedcolumn. At least one sample component of the polymer sample ischromatographically separated from other sample components thereof inthe heated chromatographic column, and a property of at least one of theseparated sample components is then detected.

If necessary for a particular application, the chromatographic columncan be heated from about ambient temperature to about 100° C., oralternatively, to about 125° C. in less than about 1 hour. Higher ratesof heating can also be employed, as necessary. For example, thechromatographic column can be heated from about ambient temperature toabout 75° C., or if necessary, to about 100° C. or to about 125° C. inless than about 30 minutes. Advantageously, the chromatographic columncan be readily cooled back to ambient temperatures at similar rates,such that the system is prepared for lower-temperature characterization.

In a preferred embodiment for this characterization protocol, thechromatographic column is preferably the relatively high-aspect ratiochromatographic column discussed above. The relatively low mass of sucha column enables it to be rapidly heated (and/or cooled) relative toconventional columns employed for high-temperature characterization.Additionally, the detector can be a temperature-insensitive detector,such as described below, that can reside external to a heatedenvironment. In such liquid chromatography systems, the column can bethe only component thereof in the heated environment. Hence, the liquidchromatography system, as a whole, can be rapidly prepared forhigh-temperature characterization, and if desired, rapidly convertedback to ambient-temperature conditions.

Mobile Phase Composition Gradient

In a further high-temperature characterization protocol, a polymersample can be characterized in a liquid chromatographic system thatemploys a compositional gradient to the mobile phase for selectivelyeluting one or more components of polymer sample from thechromatographic column. While such an approach has been employed inconnection with ambient-temperature systems, methods and apparatus forhigh-temperature liquid chromatography with a mobile-phase compositionalgradient have not been heretofore employed.

Hence, in a preferred approach, a polymer sample can be characterized byloading the polymer sample onto a chromatographic column, andmaintaining the loaded polymer sample at a temperature of not less than75° C. One or more sample components of the loaded polymer sample arethen eluted with a mobile-phase eluant having a temperature of not lessthan about 75° C. while the composition of the mobile-phase eluant iscontrolled to vary over time to separate at least one sample componentof the sample from other sample components thereof. A property of atleast one of the separated sample components is detected. As desired,the loaded polymer sample can be maintained at a temperature of not lessthan 100° C., or not less than about 125° C., and the mobile-phaseeluant can have a temperature of not less than about 100° C., or notless than about 125° C.

With reference to FIG. 6, such a preferred mobile-phase gradientapproach can be effected with a liquid chromatography system 10comprising an enclosure defining a heated environment (e.g. oven 112),where the heated environment is maintained at a temperature of not lessthan about 75° C. A chromatographic column 102 resides in the heatedenvironment. The chromatographic column 102 can comprise a surfacedefining a pressurizable separation cavity, an inlet port for receivinga mobile phase and for supplying a polymer sample to the separationcavity, an effluent port for discharging the mobile phase and thepolymer sample or separated components thereof from the separationcavity, and a stationary-phase within the separation cavity. The system10 also comprises an injection valve 210 (100) having one or moreinjection ports 108 adaptable for fluid communication with thechromatographic column 102 for injecting polymer samples into the mobilephase. The system 10 further comprises two or more reservoirs and pumpsadequate to establish a mobile-phase compositional gradient—morespecifically, a first reservoir 114 containing a first mobile-phasefluid, and a second reservoir 120 containing a second mobile-phasefluid. First and second pumps 116, 118 are dedicated to first and secondreservoirs, 114, 120, respectively. The system 10 also comprises one ormore mixing zones 144 adapted for or adaptable for fluid communicationwith the first reservoir 114 and the second reservoir 120 for mixing ofthe first and second mobile-phase fluids to form a mobile-phase eluanthaving compositions (and/or temperatures) that can vary over time. Theone or more mixing zones 144 are further adapted for or adaptable forfluid communication with the inlet port of the chromatographic column102 for eluting one or more sample components of the sample with themobile-phase eluant to separate at least one sample component of thesample from other sample components thereof. One or more detectors 130,132 are in fluid communication with the effluent port of thechromatographic column 102 for detecting a property of at least one ofthe sample components.

The system 10 can optionally comprise a third reservoir and/or a fourthreservoir (not shown) having a third and/or a fourth dedicated pump,respectively) for containing a third and/or a fourth mobile-phase fluid,with such third and/or fourth reservoir being adaptable for fluidcommunication with a mixing zone for mixing of the third and/or fourthmobile-phase fluid with one or both of the first or second mobile-phasefluids. Each of the reservoirs 114, 120 and associated pumps 116, 118are preferably isolable from each other, for example, with valves 124.

The location of the one or more mixing zones 144 within the liquidchromatography system 10 is not narrowly critical. The mixing zones 144can be, for example, directly upstream of the inlet port to thechromatographic column 102. In another embodiment, the mixing zone 144can be located in a mobile-phase column-supply line upstream and/ordownstream of the injection valve 100. In a further embodiment, thechromatographic column 102 can comprise two inlet ports, each of whichis in fluid communication with a different mobile-phase reservoir 114,120, 129, and the mixing zone is within the chromatographic column 102.

Mobile-Phase Temperature Gradient

In yet another polymer characterization protocol, a polymer sample canbe characterized in a liquid chromatographic system that employs atemperature gradient to the mobile phase for selectively eluting one ormore components of polymer sample from the chromatographic column. Whilesuch an approach may have primary applications in connection withhigh-temperature polymer characterization, the protocols can also beadvantageously employed in connection with ambient-temperature and/orcold-temperature protocols.

According to one method for characterizing a polymer sample, a polymersample is loaded onto a chromatographic column. One or more samplecomponents of the loaded polymer sample are eluted with a mobile-phaseeluant while the temperature of the mobile-phase eluant is controlled tovary over time to separate at least one sample component of the samplefrom other sample components thereof. A property of at least one of theseparated sample components is detected.

In practice, such a method can be used for precipitation-redissolutionchromatography or adsorption chromatography where the solubility oradsorptivity of the polymer sample components are controlled bymobile-phase temperature—alone or in combination with a change inmobile-phase composition. Briefly, a polymer sample is injected into amobile phase having a temperature less than the temperature at which oneor more components of the polymer sample (e.g., a polymer component, amonomer component) are soluble or not adsorbed, such that the one ormore polymer sample components precipitate and forms a separategel-phase or become adsorbed—typically depositing onto thestationary-phase media of the column. The temperature of the mobilephase is then gradually increased such that the one or more precipitatedor adsorbed components will selectively redissolve into the mobile phasebased on its respective solubility therein. Since thetemperature-dependence of the solubility or adsorptivity is a functionof both molecular weight and the particular chemistry of the component,meaningful resolution of polymer sample components and molecular-weightdistributions can be obtained.

In preferred applications, therefore, the polymer sample preferablycomprises at least one precipitated sample component after being loadedonto the chromatographic column. For high-temperature characterizationapplications, the polymer sample can comprise one or more samplecomponents that are insoluble at a temperature of less than about 75°C., or alternatively, at a temperatures of less than about 100° C., orof less than about 125° C. Moreover, because desorption from thestationary-phase of the column is based on selective resolubilization ofsample components, one or more sample components are preferablynon-desorbing from the stationary-phase media at a temperature of lessthan about 75° C., or alternatively, at a temperatures of less thanabout 100° C., or of less than about 125° C.

The method described in the immediately-preceding paragraphs can beadvantageously effected with a liquid chromatography system such as isdepicted in FIG. 6, and described above in connection with liquidchromatography based on mobile-phase compositional gradients. Referringto FIG. 6, a mobile-phase temperature gradient can be achieved over timeby heating a first reservoir 114 to maintaining a first mobile-phasefluid at a first (e.g., hot) temperature, and heating a second reservoir120 to maintaining a second mobile-phase fluid at a second (e.g., cold)temperature that is different from the first temperature. Thetemperature of the mobile phase supplied to the column 102 can then becontrolled by varying the relative amounts of the first and secondmobile-phase fluids supplied to a mixing zone 144. For high-temperaturecharacterization applications, where the column 102 resides in a heatedenvironment (e.g., oven 112), a mixing zone 144 is preferably situatedimmediately upstream of the inlet port to the column 102, and moreover,the system 10 preferably has a short transfer line from a reservoir(e.g., the third reservoir 129) to the mixing zone 144, such that thetemperature-normalizing effects of the heated environment are minimized.

More generally, a liquid chromatography system for effecting separationwith a mobile-phase temperature gradient can comprise, referring to FIG.6, a chromatographic column 102, and an injection valve 100 having oneor more injection ports 108. The system 10 also comprises a reservoir(e.g., 114) for containing a mobile-phase fluid. The reservoir isadapted for or adaptable for fluid communication with the inlet port ofthe chromatographic column. The system 10 further comprises a heater forcontrolling the temperature of the mobile-phase fluid such that one ormore sample components of the polymer sample can be eluted with amobile-phase fluid having a temperature that varies over time toseparate at least one sample component of the sample from other samplecomponents thereof, and a detector in fluid communication with theeffluent port of the chromatographic column for detecting a property ofat least one of the sample components.

The particular design for the mobile-phase heater is not critical. Theheater can be, for example, an enclosure defining a heated environment(e.g., oven 112) in which the chromatographic column resides, oralternatively, in which a length of a mobile-phase fluid transfer lineresides. In some cases, the heated environment can be maintained at atemperature of not less than about 75° C., or alternatively, not lessthan about 100° C., or not less than about 125° C. The heater can alsobe a heating element (e.g. resistive-heating element or afluid-heat-exchanger) in thermal communication with the reservoir, oralternatively, in thermal communication with a mobile-phase fluidtransfer line.

Column/Stationary-Phase Temperature Gradient

In a related, alternative approach, the solubility of a polymer samplecomponent can be controlled with temperature to effect a chromatographicseparation by controlling the temperature of the chromatographic columndirectly—through a temperature-control elements such as heating and/orcooling elements. The temperature of the column and its stationary-phasemedia can be directly controlled either alternatively to or in additionto controlling the temperature of the mobile phase. In preferredembodiments, the temperature of the column and/or stationary-phase arecontrollably varied while maintaining the temperature of the mobilephase approximately constant. Moreover, the temperature of the columnand/or stationary-phase can be controllably varied not only with time,but also with relative position over the length of the column.

Hence, in another preferred protocol, a polymer sample can becharacterized by loading a polymer sample onto a chromatographic column.The loaded sample is then eluted with a mobile-phase eluant. Thetemperature of the column and/or stationary-phase is controllablyvaried—directly by a temperature control element in thermalcommunication with the column—while eluting the column with themobile-phase eluant, such that at least one sample component of theloaded sample is separated from other sample components thereof. Aproperty of at least one of the separated sample components is detected.

The mobile-phase eluant can be supplied to the column at a temperaturethat is constant over time or alternatively, that varies over time. Toeffect precipitation of a sample component in aprecipitation-redissolution chromatographic separation, the temperatureof the column can also be directly controlled while loading the sampleonto the column, such that at least one sample component precipitates oradsorbs onto the stationary-phase media.

A number of system configurations can be employed to achieve directtemperature control of the chromatographic column. Preferably, forexample, the temperature of the column is directly controlled with atemperature-control element in direct thermal communication with thecolumn. The temperature-control element can be a heating element or acooling element. Exemplary temperature-control elements can include, forexample, a resistive-heating element or a fluid-heat-exchanger inthermal communication with the column.

Reduced-Sensitivity Detectors

In yet another polymer characterization protocol, a polymer sample canbe characterized in a flow characterization system (e.g., liquidchromatographic system) that employs a detector that is less temperaturesensitive than conventional detectors. That is, the detector (e.g., amass detector) can encounter larger variations in sample temperaturewithout substantially affecting detection of a property of interest.Moreover, the detector preferably does not have to be equilibrated tothe same temperature as the sample being characterized. A system havingsuch a detector is advantageous in several aspects. First, a detectorhaving a reduced temperature-sensitivity allows for a greater degree ofvariation of the heated environment (e.g., oven). As such, a lessexpensive heated environment can be employed. Moreover, the heatedenvironment can be accessed, at least briefly, during a high-temperaturecharacterization protocol without substantially impacting the detectiondata. As an additional advantage, the temperature-insensitive detectorcan, in some cases, be located external to the heated environment. Assuch, the size of the heated environment can be reduced, allowing lessexpensive equipment. Moreover, the rate at which the components of thecharacterization system can be heated up and/or cooled down is improved,since thermal equillibration of the detector will not be required.

Hence, a flow characterization system (e.g., liquid chromatographysystem 10) effective for high-temperature characterization of a polymersample can comprise, with reference to FIG. 6, a enclosure defining aheated environment (e.g., oven 112). The heated environment ismaintained at a temperature of not less than about 75° C. and has atleast about ±0.5° C. variation in temperature. A liquid chromatographysystem 10 also comprises a chromatographic column 102 residing in theheated environment. The flow characterization system further comprisesan injection valve 100 having one or more injection ports 108, areservoir (e.g., 114) in fluid communication with the inlet port of thechromatographic column 102 and/or with detector 130, and one or moredetectors 130 132 in fluid communication with the effluent port of thechromatographic column 102 or the injection port 108 for detecting aproperty of at least one of the sample components. At least one of thedetector is insensitive to variations in temperature of about ±0.5° C.

In some embodiments for the flow characterization system, the heatedenvironment is maintained at a temperature of not less than about 100°C.; or alternatively, at a temperature of not less than about 125° C.Moreover, the heated environment can have a variation in temperature ofat least about ±1° C., with the detector being insensitive to thevariations in temperature of about ±1° C. Alternatively, the heatedenvironment can have a variation in temperature of at least about ±2°C., or in some applications, at least about ±5° C., with the detectorbeing insensitive to the variations in temperature of about ±2° C. or insome applications, of about ±5° C., respectively. The detector is mostpreferably an evaporative light scattering detector (ELSD).

Hence, in a preferred liquid chromatography protocol, a polymer samplecan be characterized by separating at least one sample component of apolymer sample from other sample components thereof in a chromatographiccolumn residing in a heated environment. The heated environment ismaintained at a temperature of not less than about 75° C., while avariation in the temperature of the heated environment of at least aboutof at least about ±0.5° C. is allowed. A property of at least one of theseparated sample components is detected with a detector insensitive tothe about ±0.5° C. variation in temperature of the heated environment.

In variations of the preferred protocol, the allowed variation intemperature of the heated environment can be at least about ±1° C., orin some cases, at least about ±2° C. or at least about ±5° C., and thedetector is insensitive to the about ±1° C., or in some cases, at leastabout ±2° C. or at least about ±5° C. variation in temperature of theheated environment, respectively. In any of such cases, the heatedenvironment can be maintained to be not less than about 100° C., oralternatively, not less than about 125° C.

High-Temperature Flow-Injection Analysis

In a preferred high-temperature flow-injection analysis protocol, apolymer sample can be characterized by serially injecting a plurality ofpolymer samples into a mobile phase of a continuous-flow detector. Aproperty of the injected samples or of components thereof is detectedwith a continuous-flow detector. The polymer samples are maintained at atemperature of not less than about 75° C. during a period of timeincluding from when the samples are injected into the mobile phase ofthe continuous-flow detector to when the property of the injectedsamples or of a component thereof is detected.

In alternative approaches, the polymer samples can be maintained at atemperature of not less than about 100° C., or of not less than about125° C. during the period of time including from when the samples areinjected into the mobile phase of the continuous-flow detector to whenthe property of the injected samples or of a component thereof isdetected.

Calibration Methods and Standards for Flow Characterization Systems

Flow characterization systems are typically calibrated using calibrationstandards having known properties. For gel permeation chromatography(GPC), for example, calibration standards comprising known molecularweights can be used to calibrate the GPC system. Typically, acalibration standard comprises a heterogeneous polymer component havinga number of polymer subcomponents that differ with respect to thecalibrating property. Such subcomponents are typically referred to as“known standards” or, simply, “standards” that are well characterizedwith respect to the calibrating property of interest. For molecularweight (or hydrodynamic volume), for example, a calibration standardtypically comprises polymer standards having the same repeat unit, buthaving well-defined and well-characterized differences with respect tomolecular weight (or hydrodynamic volume).

It is generally preferred to calibrate a flow characterization systemwith calibration standards comprising a polymer component that haspolymer molecules with the same repeat units as the as the targetpolymer molecule being characterized by the system. For example, ifpolymer samples comprising polyisobutylene polymer components are thetarget polymer samples being characterized, the calibration standardalso preferably comprises polyisobutylene polymer components.

However, because adequate standards are not generally available for eachof the many different polymers being investigated, investigators havelong employed “universal calibration” approaches. For GPC, universalcalibration is based on the premise that the multiplication products ofintrinsic viscosities and molecular weights (hydrodynamic volumes) areindependent of polymer type. Mark-Houwink parameters, which describe themolecular weight dependence on intrinsic viscosity for a particularpolymer, can be used to create universal calibration plots from actualcalibrations performed with available calibration standards such aspolystyrene. Although such “universal calibration” approaches can beused to calibrate for polymer molecules for which direct physicalstandards are not available, are difficult to obtain, are expensiveand/or are unstable, such practices typically introduceerrors—particularly if values of intrinsic viscosities are taken fromliterature rather than measured directly under the particular conditionsto be use for the polymer characterization system.

Despite such inaccuracies, such “universal” standards are frequentlyemployed because they offer another desirable attribute—extremely narrowpolydispersities that enable the convenience of a “single-shot”calibration. That is, calibration of the flow characterization systemcan be effected by introducing a single polymer sample having, andtypically consisting essentially of a single polymer component, thepolymer component comprising a number of subcomponents (e.g.,standards), each of which comprises polymer molecules having the samerepeat unit but varying with respect to molecular weight (hydrodynamicvolume) of those polymer molecules. However, such a “single-shot” or“one-shot” calibration approach is most practical if the determinedmolecular weight (hydrodynamic volume) distribution peaks are verynarrow—with polydispersity indexes of about 1.0. Single-shot calibrationwith polymer components having broad-band distributions, rather thannarrow-band distributions are generally ineffective for calibrationpurposes due to inadequate resolution. See, for example, FIG. 22A andExample 25. Presently, calibration standards comprising polymercomponents having narrow-band distributions are available for relativelyfew types of polymer molecules, such as polystyrene—commonly used fororganic solvent systems and poly(ethylene oxide) orpoly(ethyleneglycols)—commonly used in aqueous systems.

While polystyrene or other narrow-band calibration standards can be useddirectly, with molecular weights (hydrodynamic volumes) or otherproperties reported as, for example, “polystyrene-equivalent” molecularweights (hydrodynamic volumes), such an approach does not provideaccurate absolute values for the property of interest, and as such, maynot necessarily provide a meaningful basis for direct comparison betweensystems.

The options based on conventional methodologies for calibratingcharacterization systems for target polymer samples for which polymercomponents with narrow-band distributions are not available are notattractive for combinatorial polymer chemistry applications. One could(1) calibrate with a mixture of narrow-band standards comprised ofpolymer molecules having different repeat units than those of the targetpolymer sample; (2) rely on universal calibration and/or (3) performrepetitive, “multi-shot” calibration runs with calibration polymersamples consisting of a single, broader-band polymer component. Asnoted, the former alternatives have inherent inaccuracies. The latteralternative is time consuming. The latter approach can also beexpensive—particularly where repetitive calibrations are required andthe standards are not reusable, for example, due to degradation overtime and/or during the calibration process. Hence, while suchalternatives may have been acceptable for conventional polymer chemistryresearch, they are inadequate for applications that demand both accuracyand high-speed calibration at reasonable costs—such as combinatorialpolymer research applications.

Accordingly, compositions and methods are disclosed herein that allowfor accurate, rapid, “single-shot” characterization of polymercharacterization systems. The compositions disclosed herein are“single-shot” calibration standards that provide calibration accuracyequivalent to a series of “multi-shot” calibrations with polymercomponents having the target polymer being characterized.

Briefly, an indirect calibration standard of the present invention is acomposition that consists essentially of a polymer component. Thepolymer component comprises a plurality of narrow-band polymersubcomponents, each of which can be a narrow-band polymer standard. Eachof the narrow-band polymer standards preferably has a different knownmolecular weight, a polydispersity index ranging from about 1.00 toabout 1.10, and a hydrodynamic volume that is substantially equivalentto the hydrodynamic volume of a series of broad-band target-polymerstandards. The target-polymer standards are preferably target-polymerstandards, each having a different known molecular weight, and having apolydispersity index of more than about 1.10. Because the polymermolecule of the narrow-band polymer standards is different the polymermolecule of the broad-band target polymer standards (i.e., thenarrow-band polymer standards have a different repeat structure from thebroad-band polymer standards) the actual molecular weights of thecorresponding polymer standards will be different.

More specifically, an indirect calibration standard is a compositionthat consists essentially of a heterogeneous polymer component. Thepolymer component comprises a plurality of first, narrow-band polymerstandards (subcomponents) and a continuous liquid-phase in which thenarrow-band polymer standards can be dissolved, emulsified and/ordispersed. Each of the narrow-band polymer standards has apolydispersity index of about 1 and each comprises polymermolecules—with the same repeat structure as, but with a differenthydrodynamic volumes than—the polymer molecules of other narrow-bandpolymer standards. Significantly, the hydrodynamic volume of eachpolymer molecule for a given standard is substantially equivalent to(i.e., the same as) the hydrodynamic volume of a corresponding targetpolymer standard molecule. Each of a plurality of target polymerstandards comprise one of the corresponding target polymer molecules.The target polymer standards are typically wide-band polymer standards,and are, in any case, preselected to include target polymer moleculeshaving the same repeat structure, but with hydrodynamic volumes thatvary over a range of hydrodynamic volumes sufficient to prepare aneffective calibration curve (e.g., molecular weight vs. retention time).The actual molecular weights of the narrow-band polymer molecules willtypically be different than the actual molecular weights of thecorresponding target-polymer molecules.

In a preferred application, for example, where the first, narrow-bandpolymer component is a polystyrene component, the indirect calibrationstandard is a composition that comprises two or more polystyrenestandards and a continuous liquid-phase. Each of the polystyrenestandards have a polydispersity index of about 1 and comprisepolystyrene molecules having a hydrodynamic volume substantiallyequivalent to the hydrodynamic volume of a preselected target polymerstandards. The target polymer standards are a preferably a polymer otherthan polystyrene. A set of the two or more target-polymer standards cancomprise the two or more preselected target-polymer molecules. The twoor more target polymer molecules are preselected to have hydrodynamicvolumes that vary over a range of hydrodynamic volumes sufficient toprepare an effective calibration curve (e.g., molecular weight vs.retention time).

The number of narrow-band polymer components generally corresponds tothe number of target-polymer components, and can generally range fromtwo to about ten, but can be 5 or more, or 10 or more, and is preferablyabout 5. The polydispersity index of the narrow-band polymer standardscan range from about 1.0 to about 1.10, and preferably ranges from about1.0 to about 1.05. Preferred target polymers include polymers for whichpresently available polymer standards have a polydispersity index ofless than about 1.10, are not readily available, are prohibitivelyexpensive and/or are not stable under the anticipated characterizationconditions. Exemplary target polymers include polyisobutylene,polyethylene, polybutylacrylate, polypropylene, polymethylmethacrylate,polyvinylacetate, polystyrene sulfonic acid, and polyacrylamide, amongothers.

The indirect calibration standards of the present invention can beprepared as follows. In one set of steps, two or more target-polymerstandards with known molecular weights (e.g., peak molecular weightand/or average molecular weight) are serially and individually loadedinto a polymer characterization system—preferably a liquidchromatography system, and more preferably a size exclusionchromatography system. Each of the target polymer standards comprisestarget polymer molecules. Each of the target polymer molecules is apolymer other than a narrow-band polymer, preferably with apolydispersity index of more than about 1.10, and each target polymermolecule has the same repeat structure as, but a different hydrodynamicvolume than, other target polymer molecules. The hydrodynamic volume ofthe target polymer molecules is determined for each of the individuallyloaded target polymer standards (subcomponents).

In a second set of steps, performed before or after the first set ofsteps, two or more narrow-band polymer standards are loaded into thepolymer characterization system. Each of the loaded narrow-band polymerstandards has a polydispersity index of about 1 and comprises anarrow-band polymer molecule. Each narrow-band polymer molecule has thesame repeat structure as, but a different hydrodynamic volume than,other narrow-band polymer molecules. The hydrodynamic volume of thenarrow-band polymer molecules is determined for each of the loadednarrow-band polymer standards.

After the first and second set of steps, two or more narrow-band polymerstandards that comprise narrow-band polymer molecules having ahydrodynamic volume substantially equivalent to the hydrodynamic volumeof a target polymer molecule are selected. A composition comprising theselected narrow-band polymer standards is then formed. The compositionpreferably consists essentially of the selected narrow-band polymerstandards and a continuous liquid-phase, but may include otheradditives, etc. for control purposes.

In an exemplary method for preparing preferred polystyrene calibrationprotocols, a first target-polymer standard is loaded into a polymercharacterization system. The first target-polymer standard comprisestarget-polymer molecules other than the narrow-band polymer. Thehydrodynamic volume of the target polymer molecules are determined. Asecond target polymer subcomponent is loaded into the polymercharacterization system. The second target polymer component comprisestarget polymer molecules other than polystyrene. The second targetpolymer molecules have the same repeat structure as, but a differentmolecular weight than, the first target polymer molecules. Thehydrodynamic volume of the second target polymer molecules isdetermined. Preferably, one or more additional target polymer standardsare serially loaded into the polymer characterization system. The one ormore additional target polymer standards each comprise one or moreadditional target-polymer molecules other than polystyrene. The one ormore additional target polymer molecules each have the same repeatstructure as, but a different molecular weight than, the first targetpolymer molecule, the second target polymer molecules and otheradditional target polymer molecules. The hydrodynamic volumes of the oneor more additional target polymer molecule are determined. A series ofpolystyrene standards are loaded into the polymer characterizationsystem. Each of the loaded polystyrene standards has a polydispersityindex of about 1 and comprises polystyrene molecules having a differenthydrodynamic volume than other polystyrene molecules. The hydrodynamicvolume of the polystyrene-molecules is determined for each of the loadedpolystyrene standards. Polystyrene standards having polystyrenemolecules with a hydrodynamic volume substantially equivalent to thedetermined hydrodynamic volumes of the target polymer molecules areselected. A composition comprising the selected polystyrene standards(subcomponents) is then formed.

A polymer characterization system can be calibrated with the indirectcalibration standards described above and/or prepared as describedabove. Briefly, the calibration composition is loaded into a polymercharacterization system. A property of the narrow-band (e.g.,polystyrene) components of the injected composition is detected and/ordetermined. A correlation is prepared by assigning the value for thedetected property of each of the narrow-band standards to thecorresponding target polymer standards.

Once a polymer characterization system has been calibrated, a pluralityof target polymer samples can be screened as described herein.

Multi-System, Rapid-Serial Polymer Characterization

The high-throughput rapid-serial flow characterization systems can beadvantageously applied in combination with other polymercharacterization systems for effectively and efficiently characterizinga plurality of polymer samples.

In a general case, a plurality of polymer samples, preferably four ormore polymer samples (e.g., in a library of polymer samples) areserially screened (characterized) for a first property of interest witha first characterization system. The first characterization system hasan average sample-throughput of not more than about 10 minutes persample, and in preferred approaches, is a flow characterization system.At least one of the four or more samples screened with the firstcharacterization system is then screened for a second property ofinterest with a second characterization system. Additional screeningswith additional characterization systems can also be effected.

The second polymer characterization system can be, but is notnecessarily a flow characterization system, and moreover, can have, butdoes not necessarily have, an average sample-throughput of not more thanabout 10 minutes per sample. The first and second properties of interestcan be the same or different. The first and second characterizationsystems can likewise be the same or different. For example, eachcharacterization system can be a liquid chromatography system, each canbe a flow-injection analysis system, or one can be a liquidchromatography with the other being a flow-injection analysis system.

In one approach, the two or more characterization systems can be used toscreen each of a plurality of polymer samples for two or more propertiesof interest—one property being determined by one system, anotherproperty being determined by a second system, etc. More specifically,each of the four or more samples screened with the firstcharacterization system can be screened for the second property ofinterest with the second characterization system.

In a preferred application of such approach, in which two liquidchromatography systems are employed, a polymer sample is withdrawn froma sample container, and a first portion of the withdrawn sample isinjected into a mobile phase of the first liquid chromatography system.A second portion of the withdrawn sample is then injected into a mobilephase of the second liquid chromatography system. Each of the injectedsamples are then separated, and a property of the samples or of acomponent thereof is detected in each of the respective systems. Thesesteps can be repeated in series for additional polymer samples.

In an alternative approach, a first characterization system can be usedto prescreen each of a plurality of polymer samples for a first propertyof interest, and then a second characterization system can be used torescreen certain selected polymer samples—for the same or for adifferent property of interest—with the selection for the second screenbeing based on results from the first prescreening. Briefly, four ormore samples are screened to determine a first property of interest in afirst screen. A figure of merit is determined for the four or moresamples. The figure of merit is preferably based, at least in part, onthe first determined property of interest. The determined figure ofmerit for the four or more samples is compared with a predeterminedthreshold value for the figure of merit. The threshold value can bebased, for example, on results with a then-best-known system. Thosesamples of the four or more samples that favorably compare with thepredetermined threshold value for the figure of merit are then screenedwith the second characterization system. In a preferred embodiment, onlythose samples that favorably compare to the predetermined figure ofmerit are screened with the second characterization system.

Non-Flow Characterization Systems

In non-flow polymer characterization systems, the polymer sample isdetected statically without flow of the sample. With reference to FIG.1A, non-flow characterization processes may be effected with a samplepreparation (steps A, D and E) or without a sample preparation (steps Dand E).

For rapid screening of combinatorial libraries of polymers, is it oftennot necessary to know the polydispersity index (PDI). In such cases,parallel light scattering systems may be advantageously employed.Preferably, the polymer samples are diluted in preparation forlight-scattering detection, as described for the serial flowcharacterization approach. The preparation step can be effected in arapid-serial, a parallel or a serial-parallel manner.

In a rapid-serial embodiment, a light-scattering detector, such as adynamic light-scattering (DLS) detector, can be mounted on a platformfor staging over an array of polymer samples. The DLS detector can thenserially detect the light scattered from each of the samples insequence. Automated relative motion can be provided between theDLS-platform and the array of polymer samples by robotically controllingthe DLS-platform and/or the array of sample containers.

In one parallel embodiment, an entire library of polymers can beilluminated and scattered light can be detected from every sample at thesame time. The concentration of polymer in each well may be derived inparallel by using parallel absorbency or refractive index measurements.In this embodiment, the detector can be a static light-scattering (SLS)detector or a dynamic light-scattering (DLS) detector.

In another parallel embodiment, a property of two or more polymersamples is detected simultaneously (i.e., in parallel) with two or morelight-scattering detectors positioned in appropriate relation to thesamples. In a preferred system, the light-scattering detectors aredynamic light-scattering (DLS) detectors, and preferably, fiber-opticDLS detectors. Such a system can also be employed in a pure-parallel, aserial-parallel or hybrid serial-parallel detection approach forscreening four or more polymer samples, such as a combinatorial libraryof polymerization product mixtures arranged in an array of samplecontainers. Here, two or more DLS detectors can be mounted on a commonplatform for staging over the array of polymer samples. The two or moreDLS detectors can detect the light scattered from two or more of thesamples in parallel, and then the DLS-platform (or the array) can bemoved such that the two or more DLS detectors can be serially advancedto the next subset of polymer samples. Automated relative motion can beprovided between the DLS-platform and the array of polymer samples byrobotically controlling the DLS-platform and/or the array of samplecontainers. The number of DLS probes employed in the system can rangefrom 2 to the number of polymer samples included within a plurality ofpolymer samples (as generally discussed above).

A preferred configuration thereof can be a non-flow, immersion ornon-immersion parallel DLS configuration. Briefly, with reference toFIG. 24, a parallel DLS system can comprise an array 410 of two or moreDLS probes 420, 420′, 420′ configured in a spatial relationship withrespect to each other. Each probe 420, 420′, 420″ can include atransmitting optical fiber 425, 425′, 425″ and a receiving optical fiber430, 430′, 430″. Although shown in FIG. 24 as being immersed, the probes420, 420′, 420″ can also be positioned over the samples of interest in anon-immersed configuration. Each probe 420, 420′, 420″ further comprisesa single-mode fiber coupler, also referred to as an optic (not shown),suitable for transmitting incident light to a sample and/or collectingscattered light from a sample. These couplers can preferably consist,for example, of a gradient refractive index (GRIN) lens aligned to asingle-mode optical fiber—and be mounted at an angle of 45 degrees withrespect to each other to provide for a measurement angle of 135 degrees.Other couplers and/or configurations known in the art can also beeffectively employed. A laser light can be provided from laser 435 andcoupled into the transmitting optical fibers 425, 425′, 425″ by means ofthe fiber-optics array 440. The coupled laser light can be deliveredinto the sample 20 and scattered by one or more particles of the polymersample. The scattered light can be collected via one or more optics, asdescribed above, and coupled into the receiving optical fiber 430, 430′,430″. The receiving optical fiber 430, 430′, 430″ can be in opticalcommunication with a detector array 450 (e.g., an array of avalanchephotodiodes (APD)). Measurements and photon autocorrelation can be takenin a serial manner using commercially-available autocorrelator boards,such as the ALV 5000/E (ALV GmbH, Langen, Germany). The hydrodynamicradius, Rh, and the polydispersity index (PDI) can be determined fromthe detected scattered light with commercially-available software. Othersuitable configurations can also be arranged by a person of skill in theart.

In each of the aforementioned embodiments, the light-scattering detectorcan, depending on its design characteristics, be immersed in the polymersample during detection or, alternatively, be positioned near thesurface of the polymer sample for detection without immersion therein.

The following examples illustrate the principles and advantages of theinvention.

EXAMPLES Example 1 Auto-Sampling with Single Robotic Arm

This example demonstrates rapid, automated (robotic) preparation andsampling of polymer libraries using one robotic arm.

Conventional, Commercially-Available Auto-Sampler

A conventional, commercially-available auto-sampler was evaluated. AGilson®, (Middleton, Wis.) Model 215 is described by Gilson® as acomputer-controlled XYZ robot with stationary rack. It was mounted witha steel needle probe, a syringe pump, and a valve and sample loopconnected to an HPLC system. This auto-sampler, as programmed byGilson®, required slightly more than 90 seconds to perform the followingsequence of operations: (1)drawing 100 μL water from position 1 of amicrotiter plate; (2) loading a 50 μL sample loop with the water; (3)actuating the injection valve to inject the sample into the flow system;(4) cleaning the probe needle by flushing in preparation for the nextsample; and (5) repeating steps (1) through (4) with water from a secondposition 2 of the same microtiter plate. The Gilson auto-sampler'scomputer interface did not allow the user to program a new samplecontainer (e.g., reactor block or sample block)configurations—geometries or locations. Also, the robotic arm speed wasnot controllable, and the probe was incapable of liquid level-sensing.

Auto-Sampler of the Invention

The following describes the design and operation of the auto-sampler200, probe 201, loading port 204, and injection valve 210 (100) shown inFIG. 4 and discussed in connection therewith.

A programmable XYZ robotic arm (RSP 9651, Cavro Scientific Instruments,Inc., Sunnyvale, Calif.) mounted on a platform was fitted with afluoropolymer-coated steel needle probe (Cavro part # 722470), a 500 μLpiston syringe pump (Cavro, model XL 3000) connected to the needle probeby flexible fluoropolymer tubing, and a fluoropolymer probe wash/wastestation was mounted on the platform. Features of the RSP-9651 includecapacitance based liquid-level sensing, optical step loss motiondetection and completely programmable motor speeds and accelerationprofiles. A serial interface, electrically actuated 8-port valve (modelEHC8W, Valco Instruments Co. Inc.) was mounted to the platform,controlled by the same computer as the sampler. The valve was mountedwith two 50 μL sample loops, a waste line, and a port comprising afluoropolymer liner in a steel nut (Valco, VISF-1), sized to fit a 22gauge needle (0.028 in. O.D.) for manual loading of samples with asyringe. The inner diameter of the steel nut was milled larger (from0.0645 in. to 0.076 in.), and the outermost 0.25 in of the fluoropolymerliner was enlarged within the nut to an inner diameter of ca. 0.042 in,to accommodate the coated sampler probe needle, which has an outerdiameter of 0.0425 in. With the probe needle inserted 0.20 in into theport, it was found that the mating fluoropolymer surfaces prevented anyleaking of fluid as the sample introduced fluid into the port, even atflow rates exceeding 60 mL/min. In this configuration, it was stillpossible to manually load individual samples into the loops on the valvewithout leaking, using a hand-held syringe with a 22-gauge needleinserted fully into the same port.

The valve was also fitted with inlet and outlet flow lines leading to anHPLC system. The flow was provided by two pumps (Waters, model 515)capable of generating a solvent gradient, and the chromatography systemwas provided with fittings for inserting columns, filters, and detectionsystems including a light scattering detector (Precision Detectors,model PD 2020) enclosed within the housing of a refractive indexdetector (Waters, model 410). The systems also had a UV detector(Waters, model 486). The light-scattering detector simultaneouslymeasured the static light scattering signals at 15 and 90 degrees, andthe dynamic light scattering signal at 90 degrees. An interface box (264in FIG. 2) acquires signals from all detectors.

A 96-well microtiter plate filled with water was placed on the platform,the syringe pump and probe were primed with water, and the computer wasprogrammed with the locations and of the plate, the wash and wastestations, and the valve port. The instrument was programmed, and thefollowing sequence of operations were executed: (1) drawing a 100 μLsample from position 1 of the microtiter plate; (2) loading the 50 μLsample loop with 80 μL of the drawn sample; (3) actuating the valve toinject the sample into the flow system; (4) expelling the remainingsample to waste and rinsing the inlet port of the valve with 200 μL offresh diluent; (5) moving the probe to the cleaning station and cleaningwith an additional 200 mL of diluent in preparation for the next sample;and (6) repeating steps (1) through (5) with each samples from positions2-96 of the microtiter plate.

All of these operations were performed with an average sample-throughputof less than 8 seconds per sample. Such rapid-sampling rate is wellsuited to the rapid characterization methods of this invention.

Example 2 Auto-Sampler with Two Robotic Arms

This example demonstrates rapid, automated (robotic) preparation andsampling of combinatorial libraries using two robotic arms, allowing formultiple, simultaneous analyses.

A robotic sampler was prepared in a similar manner to Example 1, exceptusing a two-arm XYZ robot (Cavro, model RSP 9652), two injection valves(Valco, model EHC8W), and four pumps (Cavro, model XL 3000). For eacharm, two pumps were connected in series to a single probe needle on thearm, one pump fitted with a 500 μL syringe, and one pump with a 5000 μLsyringe. In this configuration, good flow precision was obtained withthe smaller volume pump when needed, while the larger volume pump candeliver instantaneous flow rates of approximately 300 mL/min and overallflow rates greater than 100 mL/min, allowing for very rapid rinsing,washing, and sample manipulation.

Liquid samples from an array of vessels were rapidly loaded and injectedusing this system, with intermittent steps including washing andrinsing, in a manner similar to that described in Example 1. Theseoperations were performed with an average sample-throughput of about 4seconds per sample.

Example 3 Precipitation—Redissolution Chromatography

This example demonstrates the use of a liquid chromatography system forrapid chromatographic separation of polystyrene polymer standards usingprecipitation-redissolution chromatography with a mobile-phasecomposition gradient. The results provided a calibration for thechromatographic system and conditions.

The robotic auto-sampler and injection valve set-up as in Example 1 wasfitted with two sample loops (each having 50 microliter volume) incombination with a high-pressure liquid chromatographic (HPLC) apparatuscomprising a two-pump gradient chromatography system, primed withmethanol and tetrahydrofuran (THF) solvent. A porous crosslinkedpolystyrene monolithic column was utilized, prepared as described inFréchet et al., Journal of Chromatography A, 752 (1996) 59-66 andFréchet et al., Anal. Chem. 1996, 68, 315-321. The HPLC system wasconfigured such that the combined flow of the pump system passed throughthe valve, the column, and then to a UV chromatographic detector. Theentire system, including pump control and data acquisition from thedetector was computer-controlled.

Filtered solutions in THF of 12 commercially available (Aldrich ChemicalCo. Inc.) narrow molecular weight distribution polystyrene standards ofvarious molecular weights were dissolved in THF at a nominalconcentration of 5.0 mg/mL. Nominal molecular weights ranged from 760g/mol to 1,880,000 g/mol. Each of these polymer samples were seriallyinjected into the mobile phase of the liquid chromatography system whilevarying a range of chromatographic parameters, including total pump flowand gradient composition and speed, to obtain reasonable separation ofthe various standards in a short time.

In one experiment, the following conditions were chosen:

TABLE 1 Mobile-Phase Conditions Time (min) Parameter Value 0.0 Totalflow 10 mL/min. 0.0 Starting Solvent 30% THF:70% Methanol Composition0.35 Begin Linear Gradient To 70% THF:30% Methanol 1.20 End Gradientmaintain at 70% THF:30% Methanol 1.50 Begin Linear Gradient to initialsolvent composition 1.60 Initial Solvent Reestablished (30% THF:70%Methanol) Composition

The resulting chromatographic traces showed a linear increase in UVabsorbance during the gradient due to the linear change in solventcomposition. The profile of this gradient, measured with no sampleinjected, can be subtracted from each chromatogram to simplify theappearance of the raw data obtained for each sample. Using thechromatographic conditions described above, the following peak retentiontimes for the standards were measured:

TABLE 2 Peak Retention Times for Polystyrene Standards Nominal MolecularWeight Retention Time (min) 760 Not observed 3700 Not observed 137000.7987 18700 0.8785 29300 0.9323 44000 0.9794 114200 1.0440 2124001.0849 382100 1.1195 679000 1.1430 935000 1.1458 1880000 1.1650

The results of Table 2 comprise a calibration of the column andchromatographic conditions—thereby allowing subsequent determination ofpeak molecular weight or molecular weight distribution for samples ofunknown molecular weight.

Example 4 Rapid Flow-Injection Light Scattering

This example demonstrates a rapid flow-injection light-scattering (FILS)technique in which light-scattering measurement techniques were used todetermine an average molecular weight of a polymer sample withoutchromatographic separation of the sample.

The general layout of the system was generally as described in Example1, and as shown in FIG. 7, including an eight-port injection valve 210(See FIG. 3), a filter 212, and no column 214. A light scatteringdetector 216 and a RI detector 218 were used. Samples were injected witha syringe, by hand, into the 8-port injection valve, the valve havingtwo 50-μl injection valves. The system was maintained at a temperatureof 36° C.

M_(w) for each sample was calculated using an algorithm incorporated inthe analysis software (“Precision Analyze”, version 0.99.031(Jun. 8,1997), Precision Detectors) accompanying the PD2020. In order todetermine M_(w), points in the chromatogram representing the baselinesof the 15 and 90 degree signals and the RI signals were first selected(“baseline regions”). Linear least-squares fits of these points definedthe three baselines. Then, an integration region encompassing the mainsample peak was chosen. The software then calculated M_(w) based on theSLS and RI data and baseline values in this integration region. Thecalculation was performed in the limit of the radius of gyration, R_(g),being much less than the measurement wavelength, and the polymerconcentration in the dilute limit representing isolated molecules. Thiscalculation also used the angular form-factor, P(θ), appropriate for aGaussian-coil molecule, and fitted it to the SLS signals to extractM_(w). For polymers with M_(w) less than about 10,000 kD, this methoddetermined values of M_(w) within less than 5% of values calculatedassuming non-Gaussian-coil forms of P(θ).

R_(h) was calculated from the diffusion constant of the polymermolecules, which is obtained by fitting the photon-photon correlationfunction to an exponential. The PD2020 system was designed to allow formeasurements of R_(h) at each time-slice of the chromatogram forsufficiently low flow rates.

A series of polystyrene Mw-standards in THF as described in Example 3were measured using the system just described. The solvent flow rate was0.5 ml/min, and the injection volume was 50 μg. The width of the signalpeaks in the flow-injection analysis output data were typically 0.3 min.The centers of the SLS peaks appeared at about 0.35 min after eachinjection. For comparison, the same series of standards was run with thesame system altered to include a set of conventional GPC columns(Polymer Laboratories, 1110-6500) placed between the filter and thelight-scattering cell.

Table 3 shows the experimental M_(w) values for each of the standards,determined with a liquid chromatography system with the controlconventional GPC columns in place, and with the flow-injection analysismethod disclosed herein. The M_(w) values measured followed the expectedoverall trend except for the 13.7 kD and 0.760 kD samples. There wasfairly close quantitative agreement between measured and nominal valuesover most of the range of molecular weights. Note that there was verygood quantitative agreement between the values measured with theconventional GPC columns and the nominal values.

TABLE 3 Rapid Flow-Injection Analysis versus Conventional GPC MeasuredM_(w) (kD) Rapid Light Scattering (conventional GPC. Method measuredM_(w) Nominal M_(w) (kD) Columns) (kD) 0.76 0.72 35 2.36 2.04 17 3.703.88 21 13.7 12.3 56 18.7 18.6 53 29.3 25.3 63 44.0 44.2 80 114 106 134212 220 171 382 385 240 679 704 285 935 954 421 1880 1709 1760

The following Table 4 shows a comparison of the R_(h) values of the samesamples using (1) conventional GPC chromatography, (2) the RFLS methodof this Example and (3) the literature values of the samples. There wasgood quantitative agreement across all three sets of values for the 44kD through 935 kD samples. For samples with weights 29.3 kD and below,reliable measured values were not acquired. Literature values of R_(h)were derived from a fit to data published in: W. Mandema and H.Zeldenrust, Polymer, vol. 18, p.835, (1977). (In Table 4, NA=notavailable)

TABLE 4 Comparison of Nominal and Measured R_(h) of PolystyreneStandards Nominal M_(w) Literature R_(h) (nm) measured R_(h) (nm)measured R_(h) (nm) (kD) (T = 24 degC) (conven. columns) (no columns)0.76 NA NA NA 2.36 NA NA NA 3.70 NA NA NA 13.7 NA NA NA 18.7 3.8 NA NA29.3 4.9 NA NA 44.0 6.1 6.5 9 114 10 8.8 12 212 15 13 15 382 21 17 20679 29 23 25 935 34 27 30 1880 51 37 35

These data demonstrate that rapid, meaningful measurements of molecularweight are available by the methods of the invention, with nochromatographic separation of polymeric components. In this example, theaverage sample-throughput (i.e., measurement time) was about 0.3min/sample (about 20 seconds per sample).

As disclosed herein, other variations can be effected to achieve evenfaster measurements, for example, by controlling flow rate, sample size,acquisition times and other parameters. It is also possible to measurethe radius of gyration, R_(g), using this experimental set-up bycomparing the relative amplitudes of the 15 and 90 degree SLS signals.The system should preferably be calibrated with high precision using alow-M_(w) polymer standard in order to measure R_(g) successfully, asthe angular anisotropy of the scattering is weak.

Example 5 Rapid Size Exclusion Chromatography

This example demonstrates a rapid liquid-chromatography light-scatteringmeasurement using the short, high-aspect ratio column using the same 12commercially available polystyrene standards as used in Example 4.

The set-up was the same as in Example 4, with the exception of thepresence of a short chromatographic column (Polymer Laboratories,1110-1520, sold as a GPC “guard column”) inserted in-line between thefilter and the light-scattering cell. Briefly, the column was 7.5 mm indiameter and 5 cm height and was packed with polystyrene beads targetedto pass sample components having a molecular weight greater than about1000 without substantial separation thereof.

M_(w) was calculated using the algorithm in Precision Analyze, version0.99.031(Jun. 8, 1997), in the same way as in Example 4 over anintegration region (including elution times between 0.2 and 0.36minutes). The software allowed for automatic analysis of a series offiles without requiring the operator to manually choose integration andbaseline regions for each file individually.

A set of polystyrene standards in THF were prepared and measured asdescribed in Example 4. In addition, mixtures of polystyrene withvarying amounts of styrene monomer and polymerization catalyst (oxidizedform of CuCl with 2 equivalents of 4,4′-bis(5-nonyl)2,2′-bipyridine)were also measured. The flow rate was set to 4 ml/min in all cases.

In the case of pure polystyrene in THF, Table 5 below shows that themeasured molecular weights agree the nominal weights, with generallybetter agreement than in Example 4. In the case of the highest M_(w),the integration region partially encompassed an extraneous peak in theDRI signal at 0.34 min, possible due to contamination. Manually settingthe integration region in this case to exclude the extraneous peakyields a more accurate (1740 kD) value. In all cases, the characteristicpeak in the RI signal due to the carrier solvent eluted at times laterthan the polymers. Consequently, the solvent peak could be excluded fromthe M_(w) calculation, thereby improving the accuracy of the weightdetermination.

TABLE 5 Nominal and Measured M_(w) of Pure Polystyrene Standards NominalM_(w) (kD) Measured M_(w) (kD) 0.760 2.5 2.36 5.0 3.70 3.7 13.7 14 18.718 29.3 27 44.0 43 114 100 212 200 382 300 679 560 935 710 1880 860

For solutions containing polystyrene and styrene monomer, Table 6confirms that the measured molecular weights are independent of themonomer concentration, because the polymer (elution times rangingbetween 0.23 and 0.31 min) eluted separately from the monomers and othersmall molecule components of the sample, which elute at about 0.39 min.

TABLE 6 Nominal and Measured Mw of Polystyrene Standards with VaryingStyrene (Monomer)-to-Polystyrene Ratios styrene/polystyrene MeasuredM_(w) (kD) Nominal M_(w) (kD) (weight ratio) (short column) 2.36 0.5 6.52.36 1 2.5 2.36 2 1.7 2.36 4 1.6 2.36 8 2.0 29.3 0.5 26 29.3 1 26 29.3 226 29.3 4 25 29.3 8 25 679 0.5 560 679 1 580 679 2 600 679 4 590 679 8580

The chromatograms of the polystyrene-catalyst mixtures do not show clearpeaks attributable to the catalyst molecules. Furthermore, the heightsand shapes of the polymer SLS and DRI traces do not change appreciablywith the concentration of catalyst. Table 7, below, shows that themeasured molecular weights are independent of the catalystconcentration.

TABLE 7 Nominal and Measured Mw of Polystyrene Standards with VaryingAmounts of Catalyst measured M_(w) (kD) Nominal M_(w) (kD) catalystweight % (short column) 2.36 0.5 4.0 2.36 1 4.7 2.36 5 5.7 29.3 0.5 2529.3 1 28 29.3 5 28 679 0.5 580 679 1 570 679 5 570

Thus, these data demonstrate rapid characterization of polymer samplesand good correlation between the measured and nominal molecular weightsof polystyrene standards, with and without added monomer and catalystcomponents, using a short, high-aspect ratio chromatographic column. Thesample-throughput for the plurality of samples was about 18 seconds persample.

Example 6 Flow-Injection Light-Scattering w/Emulsion Polymer Samples

This example demonstrates flow-injection light-scattering (FILS) using adynamic light-scattering detector (DLS) to determine particle size(R_(h)) for an array of emulsion polymers.

An array of emulsion polymers was prepared as in Example 10, below, withthe following change. Solution No. 8 was replaced with water in rows 7and 8. Diluted samples of these emulsions were prepared in water byserial dilution in three stages to {fraction (1/30,000)} of the libraryas synthesized. Using the auto-sampler described in Example 1, with aflow rate of 0.3 mL/min. of water, a sample volume of 50 μL and anin-line 2 μm filter, the sample was introduced directly into the DLSdetector—without any chromatographic separation column. Samples wereinjected at 2 min. intervals. The instrument was calibrated with knownpolystyrene particle size standards (Duke Scientific, Palo Alto, Calif.,nominal R_(h) of 9.5 nm, 25 nm, 51 nm and 102 nm).

As each sample moved through the detector, between 15 and 50 independentmeasurements of R_(h) were obtained. Statistically invalid measurementswere removed and the remaining results were averaged. These R_(h) values(in nm) are shown below in Table 8.

TABLE 8 Hydrodynamic Radius Determined by Flow-InjectionLight-Scattering Row/ Col 1 2 3 4 5 6 7 8 9 10 11 12 1 45.2 42.4 39.776.0 N.D. N.D. 43.6 52.3 N.D. 68.4 84.5 N.D. 2 40.4 N.D. 36.8 N.D. N.D.N.D. 39.2 39.5 58.3 56.6 63.7 99.6 3 45.2 44.8 42.0 48.1 75.8 N.D. 47.951.1 51.7 49.0 69.9 87.9 4 41.5 37.9 38.5 69.8 39.4 86.9 41.8 42.5 48.147.8 57.2 80.8 5 42.2 39.6 38.6 37.4 41.0 44.4 45.6 58.2 71.5 46.4 60.073.9 6 N.D. 38.4 36.2 40.0 36.6 37.8 41.5 42.1 49.4 42.7 49.9 62.4 7N.D. N.D. N.D. N.D. N.D. N.D. N.D. N.D. N.D. N.D. N.D. N.D. 8 N.D. N.D.N.D. N.D. N.D. N.D. N.D. N.D. N.D. N.D. N.D. N.D.

These data show that the flow-injection light-scattering methods of thisinvention usefully screen emulsion samples for variation in particlesize. Rows 7 and 8, which contained water and no surfactant, producedunstable emulsions, as predictable, and no meaningful DLS correlationwas obtained, as was predicted.

Example 7 High-Temperature Characterization with RapidLiquid-Chromatograph

This example demonstrates rapid liquid-chromatography with a short,high-aspect ratio column and light-scattering detectors to determine themolecular weight of polymers soluble at high-temperatures.

The experimental apparatus for this example was as shown in FIGS. 7A and7B and discussed in connection therewith, except for the followingdeviations: (1) the auto-sampler probe 201 was equipped with athermostatically controlled heating element to form a heated probe(tip); (2) the sample container 202 was likewise equipped with athermostatically controlled heating element; and (3) the loading port204 and external portions of the transfer line 206 were also heated witha thermostatically controlled heating element. The remaining componentsof the system were in a temperature-controlled oven (high-temperatureGPC (Polymer Laboratories model 210)). The temperature of the oven wasmaintained at about 140° C. (but the oven could vary in temperature from35° C. to 210° C.). The injection valve was a six-port valve with thesample loop of the injection valve having volume of about 20-μl. Afilter was employed. The mobile-phase flow rate was about 4 ml/min.

The polymer samples were injected into the system at intervals of about60 seconds, filtered in-line and then chromatographically separated witha short, high-aspect ratio column packed with traditional hightemperature GPC packing material (Polymer Laboratories, 1110-1520). Theseparated sample was detected with a static light scattering detector(Precision Detectors light-scattering system (PD2040)) and a RI detector(supplied from Polymer Laboratories with the oven) configured in seriesin that order. Two computers were used to controlled the systemsubstantially as described in connection with FIG. 7B.

M_(w) was calculated using the algorithm in Precision Analyze, version0.99.031(Jun. 8, 1997), in the same way as in Experiment 4.

Commercially available polyethylene samples and a broad MWD sampleavailable from Aldrich were evaluated in this system. Table 9 shows theresults:

TABLE 9 Nominal and Measured M_(w) Sample nominal M_(w) (kD) MeasuredM_(w) (kD) Polyethylene-broad 35 24 distribution Polyethylene standard76.5 140 Polystyrene standard 68.6 74 Polystyrene standard 212.7 140

These results show the method is particularly useful for differentiatingbetween polymers having approximately a factor of 2 difference inaverage molecular weight. Thus for libraries of polymers havingmolecular weights on the order of 10³ versus polymers having molecularweights on the order of 10⁴ versus polymers having molecular weights onthe order of 10⁵ are easily distinguished. As can be seen, very rapidmeasurement (average sample-throughput of about 1 minute) of weightaverage molecular weight is possible at high temperature. The elutiontimes of these samples were all about 0.25 min, with peak widths of 0.08min. The solvent elutes at 0.46 min, with a width of 0.13 min. Thissystem can also be operated faster than in this example, as discussedabove.

Example 8 Characterization of a Combinatorial Polymer Library with RapidLC

This example demonstrates the synthesis and rapid characterization of acombinatorial library of polystyrene polymers with rapid liquidchromatography.

In a dry, nitrogen atmosphere glovebox two stock solutions (I and II)were prepared. Ligand L-1 having the structure shown below was used instock solutions I and II:

L-1 was synthesized from reductive coupling of 4-(5-nonyl)pyridine usingPd/C catalyst at 200° C. L-2 was purchased.

1-chloro-1-phenylethane (hereinafter “I-1”) was synthesized by treatmentof styrene with HCl and purified by distillation. I-2 was synthesized byreaction of commerially available divinylbenzene with HCl, followed bypurification by distillation. I-2 had the following structure:

All other materials were commercially available and were purified usingconventional techniques.

Solution I comprised 20.8 mg (0.21 mmol) of CuCl, 179.5 mg (0.44 mmol)of compound L-1, 10.9 g (0.105 mol) of styrene and 37.1 mg (0.21 mmol)of I-1. Solution II comprised 20.8 mg (0.21 mmol) of CuCl, 179.5 mg(0.44 mmol) of compound L-1, 10.9 g (0.105 mol) of styrene and 38.3 mg(0.105 mmol) of I-2. A 10-row by 11-column 110-vessel glass-linedaluminum reactor block array with approximately 800 uL volume pervessel, was prepared in a drybox under dry nitrogen atmosphere, andstock solutions I and II manually distributed to the vessels using ametering pipettor, such that elements 1-55 (5 rows by 11 columns)received 200 μL of solution I and elements 56-110 (also 5 rows by 11columns) received 200 μL of solution II. To this array was addedadditional solvent such that each row of the two 5×11 arrays received adifferent solvent, with each column received a different amount of thesolvent. The five solvents used were benzene (rows 1,6),o-dichlorobenzene (rows 2,7), m-dimethoxybenzene(rows 3,8), diphenylether (rows 4,9), and diethyl carbonate (rows 5,10). The 11 columnsreceived a gradient of dilutions in even increments from 0 to 400 uL insteps of 40 uL. In this fashion an array of 10×11 diverse polymerizationreactions were prepared, requiring a setup time of approximately 3.5hrs.

The reactor block array was sealed, removed from the glovebox, andheated to 120° C. for 15 hrs with agitation provided by an orbitalshaker. The reactor block was allowed to cool, and to each vessel wasadded 0.5 mL of tetrahydrofuran solvent, and the block was sealed andheaded at 105° C. with orbital shaking for approximately 1 hour, toallow formation of uniform, fluid solutions, and the reactor block wasallowed to cool.

Each element of the array was analyzed by rapid, automated liquidchromatography using a system substantially the same as shown in FIG. 7Aand described in connection therewith and in a manner similar to thatdescribed in Example 3. Using the automated sampler, samples of eachvial, ranging from 6 to 16 μL were drawn (5+column number=volume in μL,sampling more volume from higher numbered columns in order to have moreequal amounts of polymer, in anticipation of lower monomer conversionwith increasing dilution). Each sample was dispensed into a wellcontaining approximately 2 mL of methanol, in a polypropylene deep-wellmicrotiter plate, precipitating any solid polymeric product.

For each well, the methanol was robotically decanted and the solidpolymeric product washed with 1 mL additional methanol. The solidpolymeric product was redissolved with robotic mixing in 0.5 mLtetrahydrofuran, and a 100 μL sample of this solution was drawn and usedto load a 50 μL sample loop, followed by rapid chromatographicevaluation. During the time of each chromatographic run, the steps ofwashing and redissolving the next sample were conducted, so that eachsample injection automatically occurred at 110 sec intervals. Table 10,below, shows the peak molecular weight/1000 of the samples derived fromthe analysis. Where little or no polymer was detected in the analysis, azero is indicated. In most cases this is due to samples with lowmolecular weight, where the polymeric product precipitated into methanolas a fine slurry that was removed during the washing step and notretained for redissolution and analysis.

TABLE 10 Peak Molecular Weight/1000 Col 1 2 3 4 5 6 7 8 9 10 11 Row 148.9 46.8 44.1 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 2 48.8 44.1 0.0 40.7 40.740.0 0.0 0.0 31.1 0.0 0.0 3 49.9 44.1 40.7 40.7 40.7 45.0 42.4 40.0 0.00.0 0.0 4 49.9 44.1 44.1 36.4 38.5 0.0 0.0 0.0 0.0 0.0 0.0 5 49.9 40.033.9 31.1 0.0 0.0 0.0 0.0 0.0 0.0 0.0 6 74.3 62.4 55.6 48.8 46.8 40.036.4 33.3 0.0 0.0 0.0 7 65.5 61.0 61.0 55.6 55.6 52.1 49.9 48.8 46.842.4 40.7 8 0.0 62.4 58.2 55.6 58.2 37.1 54.4 49.9 52.1 48.8 48.8 9 68.858.2 55.6 58.2 54.4 52.1 65.5 49.9 48.8 45.0 40.7 10 65.5 49.9 44.1 38.533.3 22.8 0.0 20.4 0.0 0.0 0.0

Each element of the array was analyzed by a second time, with thefollowing changes in attempt to obtain more rapid analysis: samples ofeach vial, ranging from 10 to 60 μL were drawn (5+5×column number=volumein μL). Each sample was dispensed with agitation into a well containingapproximately 2 mL of methanol, in a polypropylene deep-well microtiterplate, precipitating any solid polymeric product. For each well, themethanol was robotically decanted. With no further washing, the solidpolymeric product was redissolved with robotic mixing in 0.5 mLtetrahydrofuran, and analyzed as above. Table 11, below, shows the peakmolecular weight of the samples derived from this second analysis. In afew cases, polymer was detected where none was seen in the previousanalysis, and the chromatographic data was more complicated due to thepresence of more low-molecular weight impurities, but in general, thesame molecular weight trends were observed.

TABLE 11 Peak Molecular Weight/1000 Col 1 2 3 4 5 6 7 8 9 10 11 Row 149.2 49.2 46.2 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 2 49.2 46.2 41.8 42.644.3 41.8 0.0 0.0 30.6 0.0 0.0 3 49.2 47.2 44.3 41.8 44.3 51.4 46.2 49.20.0 0.0 0.0 4 47.2 46.2 51.4 35.2 40.2 49.2 49.2 0.0 0.0 0.0 0.0 5 47.242.6 33.4 31.7 21.5 0.0 0.0 0.0 0.0 0.0 0.0 6 64.8 61.7 61.7 51.4 47.240.2 36.5 33.4 0.0 0.0 0.0 7 61.7 61.7 61.7 57.5 57.5 54.9 49.2 51.449.2 46.2 41.8 8 46.2 64.8 61.7 57.5 61.7 40.2 54.9 57.5 57.5 51.4 51.49 64.8 64.8 58.8 57.5 58.8 58.8 66.4 66.4 47.2 49.2 42.6 10 61.7 54.944.3 41.8 33.4 23.4 17.8 20.9 0.0 0.0 0.0

Each element of the array was analyzed by a third time, with thefollowing changes relative to the first analysis, to more slowly andthoroughly purify the polymeric product before analysis. Samples of eachvial, ranging from 10 to 60 μL were drawn (5+5×column number=volume inμL). Each sample was dispensed with agitation into a well containingapproximately 2 mL of methanol, in a polypropylene deep-well microtiterplate, precipitating any solid polymeric product. For each well, themethanol was robotically decanted. To each well was added 1.0 mL ofadditional methanol with agitation. This procedure was completed for all110 wells before any chromatographic analysis was begun, to allow moretime for extraction of low-molecular weight impurities and moreefficient settling of the solid polymeric product. Then for each well,the methanol was decanted, the solid polymeric product was redissolvedwith robotic mixing in 0.5 mL tetrahydrofuran, and the polymer wasanalyzed as above. Table 12, below, shows the peak molecular weight ofthe samples derived from this third analysis. In general, the samemolecular weight trends were observed.

TABLE 12 Peak Molecular Weight/1000 Col 1 2 3 4 5 6 7 8 9 10 11 Row 153.7 49.1 51.3 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 2 51.3 49.1 0.0 46.0 46.046.0 0.0 0.0 30.2 0.0 0.0 3 48.0 51.3 49.1 44.1 46.0 51.3 49.1 43.2 0.00.0 0.0 4 48.0 48.0 51.3 37.6 41.5 41.5 0.0 0.0 0.0 0.0 0.0 5 48.0 48.035.5 32.4 23.7 0.0 0.0 0.0 0.0 0.0 0.0 6 0.0 74.3 68.6 57.6 57.6 44.139.9 35.5 0.0 0.0 0.0 7 70.4 74.3 62.0 65.2 65.2 62.0 57.6 55.0 57.649.1 48.0 8 49.1 70.4 65.2 65.2 70.4 70.4 65.2 60.5 62.0 57.6 55.0 970.4 70.4 68.6 68.6 74.3 74.3 85.5 62.0 60.5 46.0 39.9 10 78.5 57.6 48.039.1 31.3 17.6 0.0 0.0 0.0 0.0 0.0

Example 9 Characterization of a Combinatorial Polymer Library withRaipid LC

This example demonstrates characterization of a combinatorial polymerlibrary with rapid liquid chromatography using short, high-aspect ratiocolumns in combination with light-scattering detection. The method ofscreening of Example 5 was used with a combinatorial library ofcontrolled radical polymerizations.

Materials I-1, I-2, and L-1 were prepared as in Example 8. All othermaterials were commercially available and were purified usingconventional techniques.

Five stock solutions were prepared in a dry nitrogen atmosphere glovebox(I, II, III, IV, and V), as follows: Solution I comprised 19.8 mg (0.141mmol) of 1-chloro-1-phenylethane (I-1) and 800 μL (6.98 mmol) ofstyrene. Solution II comprised 20 mg (0.2 mmol) CuCl, 174 mg of L-1(0.42 mmol), and 3.33 mL (29.1 mmol) of styrene. Solution III comprised14.2 mg of I-2 (0.07 mmol) and 800 μL (6.98 mmol) styrene. Solution IVcomprised 14.7 mg (0.105 mmol) of I-1, 10.4 mg (0.105 mmol) CuCl, 90 mg(0.022 mmol) of L-1, and 6 mL (52.4 mmol) of styrene. Solution Vcomprised 10.7 mg (0.0525 mmol) of I-2, 10.4 mg (0.105 mmol) CuCl, 90 mg(0.022 mmol) of L-1, and 6 mL (52.4 mmol) of styrene.

A 7-row by 12-column 84-vessel glass-lined aluminum reactor block arraywith approximately 800 μL volume per vessel, was prepared in a dryboxunder dry nitrogen atmosphere, and stock solutions I-V were manuallydistributed to the vessels using a metering pipettor, such that elements1-5 received a gradient of Solution I (100 μL, 50 μL, 33.3 μL, 25 μL,and 20 μL), 100 μL of Solution II, and a gradient of excess styrene (0μL, 50 μL, 66.7 μL, 75 μL, 80 μL). Elements 6-10 received a gradient ofSolution III (100 μL, 50 μL, 33.3 μL, 25 μL, and 20 μL), 100 μL ofSolution II, and a gradient of excess styrene (0 μL, 50 μL, 66.7 μL, 75μL, 80 μL). Elements 11-15 received a gradient of Solution I (100 μL, 50μL, 33.3 μL, 25 μL, and 20 μL), 100 μL of Solution II, a gradient ofexcess styrene (0 μL, 50 μL, 66.7 μL, 75 μL, 80 μL), and 200 μL ofdiphenylether. Elements 16-20 received a gradient of Solution III (100μL, 50 μL, 33.3 μL, 25 μL, and 20 μL), 100 μL of Solution II, a gradientof excess styrene (0 μL, 50 μL, 66.7 μL, 75 μL, 80 μL), and 200 μL ofdiphenylether. Elements 21-50 (a 5×6 array) received 150 μL of SolutionIV and a gradient of dilutions along each row by adding solvent (75 μL,150 μL, 225 μL, 300 μL, 375 μL, 450 μL) with a different solvent in eachrow (diethyl carbonate, benzene, o-dichlorobenzene, m-dimethoxybenzene,and diphenylether, respectively). Similarly, elements 51-80 (a 5×6array) received 150 μL of Solution V and a gradient of dilutions alongeach row by adding solvent (75 μL, 150 μL, 225 μL, 300 μL, 375 μL, 450μL) with a different solvent in each row (diethyl carbonate, benzene,o-dichlorobenzene, m-dimethoxybenzene, and diphenylether, respectively).In this fashion an array of 7×12 diverse polymerization reactions wereprepared, requiring a setup time of approximately 5 hrs. The reactorblock array was sealed using a Teflon membrane covering a silicon rubbersheet compressed with an aluminum plate bolted in place.

The array was then heated to 120° C. for 15 hrs with agitation providedby an orbital shaker. The reaction block was allowed to cool, and toeach vessel was added THF such that the total volume reached 0.8 mL, andthe block was sealed and heated at 105° C. with orbital shaking forapproximately 1 hr, to allow formation of homogeneous fluid solutions.The reactor block was allowed to cool.

Each element of the array was analyzed by rapid manner as described inExample 5, with the following procedure. Using a programmable roboticsampler, 20 μL of each vial were drawn and dispensed along with 250 μLof THF into a polypropylene microtiter plate. 100 μL of this dilutedsample was drawn and used to load a 50 μL sample loop on an HPLCinjector, followed by rapid LS evaluation. During the time of eachanalysis, the step of diluting the next sample was conducted, so thateach sample injection automatically occurred at 40 sec. intervals. Table13, below, shows the average M_(w)/1000 of the samples derived from theanalysis.

TABLE 13 Average M_(w)/1000 Col 1 2 3 4 5 6 7 8 9 10 11 12 Row 1 22.235.7 46.3 55.8 63.7 NR NR 25.9 47.6 57.3 72 78.2 2 8.65 15 22.3 26.630.4 NR NR 11.2 19.8 33.1 40.1 42.9 3 28.9 20.2 16.6 12.6 12 11.9 4434.3 29.8 20.9 17.6 16.4 4 38.9 29.6 26.1 24.1 24.2 22.9 56 51.7 45 38.730.9 27 5 47.8 34.8 23.6 18.6 15.4 14.1 59.9 48.3 33.7 25.2 22.6 18.3 640.6 28.6 15.3 12.9 12 13.1 45.8 20.8 17.7 12.3 13.3 13.8 7 40.3 30.223.2 20.9 19.5 19.2 46.8 37.4 34.2 29.7 28.6 27.8

The expected trends of decreasing molecular weight with increasingdilution were observed. This demonstrates very rapid molecular weightdeterminations in combinatorial discovery of optimal catalyticprocesses.

Example 10 Characterization of Emulsion Samples with RapidSEC—Adsorption LC

This example demonstrates rapid size exclusion chromatography (SEC),combined with adsorption chromatography for determining molecularweight, MWD and residual monomer concentration (i.e., conversion) in thepresence of water in a combinatorial library of emulsion polymers. Morespecifically, the GPC characterization of hydrophobic polymers andconversion analysis in a single run is demonstrated. In such cases, themonomer peak can often be overlapped with a peak of the solvent used forpolymerization; however, the approaches disclosed herein overcome thispotential pitfall.

This specific example describes a method for both molecular weightcharacterization of polymer as well as quantitative analysis of monomerand polymer in a sample prepared by emulsion polymerization. Thetechnique is based on combination of size-exclusion and adsorptioneffects. A size separation of polymer and monomer is obtained whilewater is adsorbed under these conditions and not interfering with theanalysis.

The system used is described in Example 3, using an eight port Valcoinjection valve, a Waters 515 pump, a Waters UV-VIS 486 detector, a LSdetector PD 2000 built inside the RI unit. (Also, a Waters 410 RIdetector was connected to the system, but not used for this particularexample. It was used in a later, related example.) A series of two 50×8mm hydrophilic columns Suprema 30 Å and 1000 Å from Polymer StandardServices were used for the analyses. (A later experiment that followedthis example combined the two columns together in a single mixed bedcolumn, which provided equivalent, but slightly better separation). Thechromatography was performed using THF as the mobile phase at variousflow rates (1, 2, 5, and 10 mL/min). The chromatographic separation wascompleted in less than 2 min per sample (at 2 mL/min) with goodresolution of separation and precision of the molecular weightdetermination at these flow rates. The separation can be obtained inabout 20 seconds (at 10 mL/min), with some impact on the precision ofthe method.

An 8-row by 12-column combinatorial library array of 96 emulsionpolymerization reactions was prepared according to the followingprocedure. Nine 20 ml vials were prepared with neat monomer, 10%surfactant solutions or initiator solution as described below, all fromcommercially available materials without further purification. Solutionvials were as follows:

Solution Vial Contents

1) styrene

2) butyl acrylate

3) methyl methacrylate

4) vinyl acetate

5) sodium dodecyl sulfate (SDS)(Aldrich, 10 wt % in water)

6) sodium dodecylbenzenesulfonate (SDBS)(Aldrich, 10 wt % in water)

7) Rhodacal A246L (A246L)(Rhone Poulenc, diluted to 10 wt % in water)

8) Dowfax 2A1 (2A1)(Dow Chemical Co., diluted to 10 wt % in water)

9) K₂S₂O₈ (4 wt % in water)

A 96-member array of glass vessels in an aluminum reaction block wasprepared. In an oxygen-free glovebox, using an automated sampler asdescribed in Example 1, three of the above 9 solutions were dispensed toeach vessel in the array, as shown in the following Table 14. Water wasadded to each vessel to bring the total volume to 500 μL. Solution 9 wasadded last to all of the vessels. The total time required for theautomated, robotic dispensing was approximately 18 minutes. Each elementof the table contains the solution number-quantity of that solution, inmicroliters.

TABLE 14 Sample-Preparation Row Col 1 2 3 4 5 6 7 8 9 10 11 12 1 1-1251-150 1-175 2-125 2-150 2-175 3-125 3-150 3-175 4-125 4-150 4-175 5-6.35-7.5 5-8.8 5-6.3 5-7.5 5-8.8 5-6.3 5-7.5 5-8.8 5-6.3 5-7.5 5-8.8 9-31.39-37.5 9-43.8 9-31.3 9-37.5 9-43.8 9-31.3 9-37.5 9-43.8 9-31.3 9-37.59-43.8 2 1-125 1-150 1-175 2-125 2-150 2-175 3-125 3-150 3-175 4-1254-150 4-175 5-12.5 5-15.0 5-17.5 5-12.5 5-15.0 5-17.5 5-12.5 5-15.05-17.5 5-12.5 5-15.0 5-17.5 9-31.3 9-37.5 9-43.8 9-31.3 9-37.5 9-43.89-31.3 9-37.5 9-43.8 9-31.3 9-37.5 9-43.8 3 1-125 1-150 1-175 2-1252-150 2-175 3-125 3-150 3-175 4-125 4-150 4-175 6-6.3 6-7.5 6-8.8 6-6.36-7.5 6-8.8 6-6.3 6-7.5 6-8.8 6-6.3 6-7.5 6-8.8 9-31.3 9-37.5 9-43.89-31.3 9-37.5 9-43.8 9-31.3 9-37.5 9-43.8 9-31.3 9-37.5 9-43.8 4 1-1251-150 1-175 2-125 2-150 2-175 3-125 3-150 3-175 4-125 4-150 4-175 6-12.56-15.0 6-17.5 6-12.5 6-15.0 6-17.5 6-12.5 6-15.0 6-17.5 6-12.5 6-15.06-17.5 9-31.3 9-37.5 9-43.8 9-31.3 9-37.5 9-43.8 9-31.3 9-37.5 9-43.89-31.3 9-37.5 9-43.8 5 1-125 1-150 1-175 2-125 2-150 2-175 3-125 3-1503-175 4-125 4-150 4-175 7-6.3 7-7.5 7-8.8 7-6.3 7-7.5 7-8.8 7-6.3 7-7.57-8.8 7-6.3 7-7.5 7-8.8 9-31.3 9-37.5 9-43.8 9-31.3 9-37.5 9-43.8 9-31.39-37.5 9-43.8 9-31.3 9-37.5 9-43.8 6 1-125 1-150 1-175 2-125 2-150 2-1753-125 3-150 3-175 4-125 4-150 4-175 7-12.5 7-15.0 7-17.5 7-12.5 7-15.07-17.5 7-12.5 7-15.0 7-17.5 7-12.5 7-15.0 7-17.5 9-31.3 9-37.5 9-43.89-31.3 9-37.5 9-43.8 9-31.3 9-37.5 9-43.8 9-31.3 9-37.5 9-43.8 7 1-1251-150 1-175 2-125 2-150 2-175 3-125 3-150 3-175 4-125 4-150 4-175 8-6.38-7.5 8-8.8 8-6.3 8-7.5 8-8.8 8-6.3 8-7.5 8-8.8 8-6.3 8-7.5 8-8.8 9-31.39-37.5 9-43.8 9-31.3 9-37.5 9-43.8 9-31.3 9-37.5 9-43.8 9-31.3 9-37.59-43.8 8 1-125 1-150 1-175 2-125 2-150 2-175 3-125 3-150 3-175 4-1254-150 4-175 8-12.5 8-15.0 8-17.5 8-12.5 8-15.0 8-17.5 8-12.5 8-15.08-17.5 8-12.5 8-15.0 8-17.5 9-31.3 9-37.5 9-43.8 9-31.3 9-37.5 9-43.89-31.3 9-37.5 9-43.8 9-31.3 9-37.5 9-43.8

The reactor block was sealed and heated to 80° C. for 4 hours withagitation. The resulting array of polymer emulsions was allowed to cooland the reactor block opened. Visual inspection indicated that polymeremulsions had formed in most of the vessels of the array.

The product emulsions were diluted 100 times with THF and analyzed usingthe system described above. Molecular-weight data were obtained bothfrom the GPC calibration curves using polystyrene standards and fromlight scattering at two different angles (15° and 90°). A quantitativeanalysis including both monomer and polymer content can be obtained fromthe peak areas. FIG. 8 shows a representative rapid gelpermeation/adsorption HPLC separation of a sample, under the conditions:column, 30×10 mm, mobile phase, tetrahydrofuran at 2 mL/min, RI and LSdetection.

Table 15, below, shows tabulated peak molecular weight as determined bythis method and the following Table 16 shows the measured conversion ineach polymerization vessel determined by relative UV-VIS areas of themonomer and polymer peaks, corrected for optical absorptivity of thecomponents. Relative molecular weight distribution information (MWD) wasalso obtained.

TABLE 15 Measured Peak Molecular Weights (kD) Col/Row 1 2 3 4 5 6 7 8 910 11 12 1 131 128 125 113 105 30 683 615 486 256 152 244 2 122 164 195138 N.D. 15 993 599 615 220 357 270 3 200 148 125 160 618 45 539 525 512210 181 185 4 215 238 160 148 N.D. N.D. 1169 740 525 322 131 250 5 138131 134 145 73 79 539 375 357 204 205 238 6 N.D. 168 168 164 172 22 1048845 474 190 195 226 7 232 244 172 181 215 119 615 474 339 172 199 238 8145 215 220 250 238 190 438 N.D. N.D. 138 190 N.D.

TABLE 16 Conversion Data Determined from Residual Monomer Detection.Col/Row 1 2 3 4 5 6 7 8 9 10 11 12 1 98.74 99.15 99.12 93.84 89.83 85.5195.01 95.84 96.12 3.25 3.27 2.00 2 96.34 98.48 97.66 92.33 0.00 88.9695.44 94.56 95.21 2.01 3.13 0.69 3 98.44 98.81 98.36 92.01 86.31 81.4093.85 94.20 96.77 3.84 7.98 3.71 4 98.89 98.80 97.53 91.28 0.00 0.0093.19 94.98 95.67 1.90 0.62 4.73 5 98.61 89.76 96.06 91.52 22.60 3.9193.67 94.79 93.66 6.97 4.44 6.72 6 0.00 94.81 86.46 76.26 82.36 0.0091.55 94.19 95.09 3.10 5.18 6.06 7 99.13 89.56 93.87 84.70 79.54 68.5494.17 63.75 82.35 5.18 5.08 5.35 8 98.64 98.16 97.65 96.07 81.28 81.9794.53 0.00 0.00 7.04 2.07 0.00

Example 11 Characterizing Emulsion Samples with SEC—AdsorptionChromatography

This example demonstrates rapid characterization of emulsion particleswith rapid size-exclusion-chromatography (SEC) with a short, high-aspectratio columns having a stationary-phase media with large pore sizes forseparating polymer emulsion particles.

Retention times were used to determine R_(h) values of latex particlesinjected into the chromatographic systems, using the equipment describedin Example 3 and short, high-aspect ratio columns (described below)packed with very a large pore size stationary phase. In this example, aseries of standard dispersions of polystyrene latex particles dilutedwith water by a factor of 200 were injected into the chromatographicsystem using water as a mobile phase and a 30×10 mm chromatographiccolumn packed with GM-3000 and GM-GEL 5000 beads (Kurita, Japan). Theconcentration of latex was detcted by both RI and LS detectors. The RIsignal was determined to be linearly dependent on the mass of polymer inthe sample.

FIG. 9 shows refractive index traces for latex particles of differentsizes from this example. The average sample-throughput for this examplewas less than 2 min. per sample.

Example 12 Characterizing Emulsion Samples with Rapid-FireLight-Scattering

This example demonstrates rapid particle-size characterization ofemulsion particles with rapid-fire static-light-scattering (SLS)detection—without chromatographic separation.

In this example, both light scattering and refractive index traces ofvarious latex particles using the same chromatographic system asdescribed in Example 4. The particle peak areas at RI trace remained thesame for particular concentration of particles regardless on theparticle size, while the areas of the peaks in the LS trace wereaffected significantly by particle size. The response of LS detectorrelative to that of RI is a function of the particle size. After acalibration, this dependence can be used for rapid particle sizedetermination of unknown samples.

FIG. 10 shows LS and RI traces obtained for latex particles of differentsizes under the same flow conditions as in Example 11.

Example 13 Rapid Reverse-Phase Chromatography w/Compositional Gradient

This example demonstrates rapid characterization of polymer samplesusing reverse phase liquid chromatographic separation of polymers basedon composition differences in the mobile phase.

In a dry nitrogen atmosphere glovebox were prepared twelve stocksolutions. L-1 was synthesized from reductive coupling of4-(5-nonyl)pyridine using Pd/C catalyst at 200° C. I-2(1-chloro-1-phenylethane) was synthesized by reaction of commerciallyavailable styrene with HCl, followed by purification by distillation.All other materials were commercially available and were purified usingconventional techniques. Solution I comprised 1.5 mL of styrene.Solution II comprised 1.35 mL styrene and 0.15 mL of n-butylacrylate.Solution II comprised 1.35 mL styrene and 0.15 mL of n-butylacrylate.Solution III comprised 1.20 mL styrene and 0.30 mL of n-butylacrylate.Solution IV comprised 1.05 mL styrene and 0.45 mL of n-butylacrylate.Solution V comprised 0.90 mL styrene and 0.60 mL of n-butylacrylate.Solution VI comprised 0.75 mL styrene and 0.75 mL of n-butylacrylate.Solution VII comprised 0.60 mL styrene and 0.90 mL of n-butylacrylate.Solution VIII comprised 0.45 mL styrene and 1.05 mL of n-butylacrylate.Solution IX comprised 0.30 mL styrene and 1.20 mL of n-butylacrylate.Solution X comprised 0.15 mL styrene and 1.35 mL of n-butylacrylate.Solution XI comprised 1.50 mL of n-butylacrylate. Solution XII comprised90 mg (0.64 mmol) of I-2, 63.4 mg (0.64 mmol) of CuCl, 584 mg (1.344mmol) of L-1, and 2 mL of diethyl carbonate. A 5-row by 11-column55-vessel glass-lined aluminum reactor block array with approximately800 uL volume per vessel, was prepared in a drybox under dry nitrogenatmosphere, and stock solutions I-XII were manually distributed to thevessels using a metering pipettor, such that column 1 elements received200 uL of solution I, column 2 elements received 200 uL of solution II,column 3 elements received 200 uL of solution III, column 4 elementsreceived 200 uL of solution IV, column 5 elements received 200 uL ofsolution V, column 6 elements received 200 uL of solution VI, column 7elements received 200 uL of solution VII, column 8 elements received 200uL of solution VIII, column 9 elements received 200 uL of solution IX,column 10 elements received 200 uL of solution X, column 11 elementsreceived 200 uL of solution XI. Solution XII was then added to allelements such that row 1 received 50 μL, row 2 received 40 μL, row 3received 30 uL, row 4 received 20 uL and row 5 received 10 uL. Thereactor block array was sealed using a teflon film covering a siliconrubber against an aluminum cap.

The array was then heated to 140° C. for 15 hr with agitation providedby an orbital shaker. The reaction block was allowed to cool, and toeach vessel was added THF such that the total volume reached 0.8 mL, andthe block was sealed and heated at 110° C. with orbital shaking forapproximately 1 hr, to allow formation of uniform, fluid solution, andthe reactor block was allowed to cool. This library of random copolymersof styrene and n-butylacrylate was expected to produce polymers with arange of molecular weights and compositions, which were tested with thefollowing system.

Adsorption chromatography was used for separation of various componentsof the reaction mixtures that contained the comonomers, (co)polymers,solvents and catalyst components. Good separation was achieved in 60seconds per sample using a short, high-aspect ratio reversed-phasecolumn and gradient of THF in water with a concave profile. The specificgradient profile allows to separate small molecules with similarretention behavior from each other as well as elute a highly retainedpolymer in a very short time. Columns of various sizes, porosities andchemistries were used for this purpose including polystyrene-basedmonoliths and silica-based porous beads.

Combination of optimum column and mobile phase parameters leads to amuch faster separation then experienced before and allows the techniqueto be used for characterization of the polymerization libraries. Thebest results were achieved with short cartridges packed with 10 μmoctadecylsilica beads. The library of 96 polymer sample mixtures wasanalyzed in 144 min (including diluting samples, chromatography andsaving the chromatograms)—demonstrating an average sample throughput ofabout 1.5 minutes per sample.

In this example, samples containing styrene, butylacrylate, (co)polymer,initiator and solvent at various concentrations were injected into a30×4.6 mm precolumn cartridge RP-18 (Brownlee) equilibrated by 27%tetrahydrofuran at 10 mL/min. Then the percentage of tetrahydrofuran inmobile phase was changed using a concave gradient profile from 27 to100% tetrahydrofuran. The chromatographic system used for this examplewas the same as that described in Example 3, however, equipped with aUV-VIS detector only. The solvent and monomers are eluted within a firstfew percent of tetrahydrofuran, polymer requires much higher percentageof tetrahydrofuran to be eluted. All five peaks representing theparticular components of the mixtures were eluted within 60 seconds.

Example 14 Comparison of Rapid GPC and Conventional GPC

This example demonstrates correlation between rapid liquidchromatography (using a short, high-aspect ratio column) andconventional GPC.

The same synthetic procedure as in Example 8 was carried out using arobotic sampler in an inert atmosphere drybox, requiring approximately20 min. to prepare the reaction array. Similar processing of the arraywas carried out as in Example 8.

Row six of the array was analyzed by RFLS as in Examples 5 and 9 todetermine values of M_(w). Row six was also analyzed by conventional GPCusing two mixed bed columns (Polymer Labs, 7.5×300 mm mixed C PL-gel).THF was used as the eluant in both cases.

Comparisons of M_(w) values obtained by both methods are shown by thefollowing Table 17.

TABLE 17 Comparison of M_(w) Values from RFLS and Conventional GPC RFLSGPC Sample (M_(w,) kD) (M_(w,) kD) 1 79.7 83.8 2 45.1 52.4 3 42.8 46.4 438.9 N.D. 5 39.7 45.7 6 37.4 40.3 7 37.2 41.9 8 34.9 39.9 9 35.5 38.4 1033.9 34.2 11 34.3 37.4

As can be seen from this table, the rapid GPC protocols disclosed hereinprovide M_(w) values in agreement with traditional GPC.

Example 15 Rapid Size Exclusion Chromatography

This example demonstrates the characterization of a plurality ofpolystyrene standards using rapid size exclusion chromatography. Thesample-throughput was 2 minutes per sample.

Two short, high-aspect ratio columns (0.8 cm×3 cm) were employed inseries. The first column was packed with Suprema Gel 30 Å and the secondcolumn was packed with Suprema Gel 1000 Å (Polymer Standard Service,Germany). The mobile-phase solvent was THF at a flowrate of 2 ml/min.Sample preparation was the same as in Example 17. The polymer samples(20 μl) were serially injected at two minute intervals (without beingoverlaid). The separated samples or components thereof were detectedwith a UV-VIS detector at 220 nm.

FIGS. 11A and 11B shows the results—overlaid as a single trace (FIG.11A) and the corresponding calibration curve (FIG. 11B). Good linearityof the calibration curve is demonstrated.

Example 16 Rapid Size Exclusion Chromatography with Enhanced Resolution

This example demonstrates the characterization of a plurality of butylrubber (polyisobutylene) samples using size exclusion chromatographywith overlaid injection and enhanced resolution. The sample-throughputwas 1½ minutes per sample.

A single, conventional chromatography column (0.75 cm×30 cm) was packedwith PL Gel Mixed-B (Polymer Labs). The mobile-phase solvent was tolueneat a flowrate of 4 ml/min. The system was calibrated using the indirectcalibration polystyrene standards and protocols of Example 26. Samplepreparation was the same as in Example 17. The polymer samples (50 μl)were serially injected at 90 second intervals (with overlaid injection).The separated samples or components thereof were detected with an ELSDdetector at 120° C. and 7 l/min of air.

FIG. 12A through FIG. 12C show the data from the experiment. FIG. 12Ashows the chromatographs of each of the samples—electronically overlaidon a single trace. The chromatograph for the “single-shot” indirectcalibration standard is shown in FIG. 12B and the correspondingcalibration curve is shown in FIG. 12C. Significantly, a relativehigh-molecular weight polyisobutylene was identified (M_(peak)=154,288;M_(w)=199,123; M_(n)=46,406; PDI˜4.3) and distinguished from other,lower molecular weight samples.

Example 17 Rapid Size Exclusion Chromatography with Enhanced Resolution

This example demonstrates the characterization of a plurality ofpolyisobutylene samples using accelerated size exclusion chromatographywith overlaid injection. The sample-throughput was 8 minutes per sample.

A series of three identical conventional chromatography column (0.75cm×30 cm) were employed, each of which was packed with PL Gel Mixed-B(Polymer Labs). The mobile-phase solvent was toluene at a flowrate of 2ml/min. The system was calibrated using polystyrene standards. Samplepreparation (dilution, mixing) was effected on each succeeding samplewhile each preceding sample was being separated. The polymer samples (50μl) were serially injected at 8 minute intervals (with overlaidinjection). The separated samples or components thereof were detectedwith an ELSD detector at 120° C. and 7 l/min of air.

FIG. 13 is a representative chromatograph from one of the samples. Asshown in FIG. 13, the representative sample comprised an earlier elutingpolymer component (M_(peak)=67,285; M_(w)=75,162; M_(n)=38,106; PDI˜2.0)and a later eluting lower molecular-weight component (M_(peak)=1,736).

The same library of polymer samples was characterized a second time withthe same liquid chromatography system except that the mobile phase wasTHF at 2 ml/min and the ELSD detector was at 50° C. and 7 l/min of air.Similar results (not shown) were obtained.

Example 18 Comparison of Rapid SEC, Enhanced Rapid SEC, and AcceleratedSEC

This example demonstrates a comparison between three preferredembodiments of the invention: rapid size exclusion chromatography (SEC),rapid SEC with enhanced resolution and accelerated SEC. Theseembodiments differ, in general, with respect to sample throughput and,in some aspects, information quality, as explained below.

Example 18A Comparison of Accelerated SEC and Rapid SEC

A combinatorial library of polystyrene polymer samples—prepared inemulsions with varying ratios of monomer to initiator—were characterizedwith two different liquid chromatography approaches: accelerated SEC andrapid SEC—adsorption chromatography.

The accelerated SEC liquid chromatography system was substantiallysimilar to that described in Example 17, with a sample-throughput of 8minutes per sample and with complete molecular weight determination(M_(peak), M_(w), M_(n), PDI, and molecular weight distribution shape).The rapid SEC-adsorption liquid chromatography system was substantiallysimilar to that described in Example 20, except with a sample-throughputof about 1-2 minutes per sample with limited molecular weightdetermination (M_(peak), M_(w), and estimate of PDI).

FIGS. 14A and 14B show the determined weight-average molecular weightfor each of the samples of the library as characterized using theaccelerated SEC (FIG. 14A) and the rapid SEC (FIG. 14B) systems. Theweight-average molecular weight deter mined by these techniques issubstantially the same—demonstrating that the rapid SEC system,operating with a throughput of about 1-2 minutes per sample, is rigorousfor determination of M_(w). The techniques varied, however, with respectto the accuracy of determined PDI values (data not shown).

Example 18B Comparison of Accelerated SEC and Enhanced Rapid SEC

A combinatorial library of butyl rubber (polyisobutylene) polymersamples were prepared, and then characterized with two different liquidchromatography approaches: accelerated SEC and enhanced rapid SEC (alsoreferred to herein as “rapid SEC with enhanced resolution”).

The accelerated SEC liquid chromatography system was substantiallysimilar to that described in Example 17, with a sample-throughput of 8minutes per sample and with complete molecular weight determination(M_(peak), M_(w), M_(n), PDI, and molecular weight distribution shape)and conversion determination. The rapid SEC liquid chromatography systemwas substantially similar to that described in Example 16, with asample-throughput of about 1½ minutes per sample and with reasonablycomplete molecular weight determination (M_(peak), M_(w), and goodestimate of PDI) and conversion determination.

FIGS. 15A through 15F show the resulting data. FIGS. 15A through 15Cshow the determined weight-average molecular weight (FIG. 15A), thedetermined polydispersity index (FIG. 15B) and the determined conversion(FIG. 15C) for each of the samples of the library as characterized usingthe accelerated SEC system. FIGS. 15D through 15F show the determinedweight-average molecular weight (FIG. 15D), the determinedpolydispersity index (FIG. 15E) and the determined conversion (FIG. 15F)for each of the samples of the library as characterized using theenhanced rapid SEC system. Comparison of the results demonstrates thatthe determined weight-average molecular weight and the determinedconversion are substantially the same for each of these techniques.Although differences can be observed between the determined values forthe polydispersity indexes of the two characterizations systems, trendsin PDI values are observable and substantially the same for the twocharacterization systems.

Example 19 Comparison of ELSD Detector and RI Detector

This example demonstrates a comparison between an evaporativelight-scattering detector (ELSD), sometimes alternatively referred to asan evaporative mass detector (EMD), and a refractive index (RI)detector. More specifically, this example demonstrates the principle ofusing a low-molecular weight insensitive detector, such as an ELSD, fordetection in liquid chromatography or flow injection analysis systems.

FIGS. 16A and 16B show chromatographic traces for the same polymersample characterized in two different liquid chromatography systems thatwere identical except with respect to the detector—one system employinga RI detector and a second system employing an ELSD detector. Comparisonof these traces (FIG. 16A, FIG. 16B) shows that the polymer sample had arelatively high-molecular weight component (M_(peak)=244,794) and arelatively low-molecular weight component (M_(p)=114). Although bothdetectors characterized the relatively high-molecular weight component,the ELSD detector was insensitive to the relatively low-molecular weightcomponent.

As discussed above, such insensitivity can be advantageously employed inconnection with the invention, particularly with respect to serialoverlaid injection of a preceding sample and a succeeding sample. Unlikethe RI detector, the ELSD detector can detect the leading edge of thesucceeding sample sooner, without interference from the trailing edge ofthe preceding sample.

Example 20 Rapid SEC—Adsorption Chromatography

This example demonstrates the characterization of a plurality ofemulsion polymer samples using rapid size exclusion chromatography (SEC)in combination with adsorption chromatography to determine molecularweight and conversion. The sample-throughput was 2-3 minutes per sample.

Two short, high-aspect ratio columns (0.8 cm×3 cm) were employed inseries. The first column was packed with Suprema Gel 30 Å and the secondcolumn was packed with Suprema Gel 1000 Å (Polymer Standard Service,Germany). The mobile-phase solvent was THF at a flowrate of 2 ml/min.Sample preparation was the same as in Example 17. The emulsion polymersamples (polystyrene, polymethylmethacrylate, polybutylacrylate andpolyvinylacetate) were serially injected at 2-3 minute intervals(without being overlaid). The separated samples or components thereofwere detected.

FIGS. 17A and 17B shows the determined conversion (FIG. 17A) and thedetermined weight-average molecular weight (FIG. 17B) for thepolystyrene samples (columns 1-4), the polymethylmethacrylate samples(columns 4-6), the polybutylacrylate samples (columns 7-9) and thepolyvinylacetate samples (columns 10-12). These data demonstrate thatSEC-adsorption chromatography can be effectively employed to determineboth molecular weight and conversion with high sample-throughput.

Example 21 High—Temperature Characterization of Polymers

This example demonstrates the characterization of a plurality ofpolystyrene and polyethylene calibration standards usinghigh-temperature liquid chromatography.

The experimental set-up was substantially as shown in FIG. 6 anddescribed in connection therewith and as follows. The auto-sampler 104′was located outside of a heated oven 112, and was equipped with a long,thermostatically-controlled heated probe 201 maintained at a temperatureof 140° C. The heated probe was substantially as shown in FIG. 5A anddescribed in connection therewith. The sample container 202 was likewiseheated and maintained at a temperature of 140° C. The loading port 204,transfer line 206, injection valve 210, in-line filter (0.2 μl, notshown), and column 102 resided in the oven 112 and maintained at atemperature ranging from 140° C. to 160° C. The injection valve 210 wasan eight-port valve substantially as shown in FIG. 3 and described inconnection therewith, with each of the sample loops having a volume ofabout 200 μl. The column was a high-aspect ratio column (2.5 cm×5 cm)packed with PL Gel Mixed-B (Polymer Labs). For the experiments ofExample 21A only, an in-line flow-splitter (not shown) was positionedafter the column and the before the detector. The flow-splitter residedin the oven, and split the separated sample stream at a ratio of about1:15 (detector:waste). For both examples 21A and 21B, an external ELSDdetector resided outside of the heated oven 112, and was in fluidcommunication with the column 102 (or flow-splitter) by means of aheated transfer line.

The following commercially available calibration standards were seriallyintroduced into the liquid chromatography system by serially withdrawingthe samples from the sample container and delivering the samples throughoven aperture 113 to the loading port 204:

Polyethylene Polystyrene (nominal Mw) (nominal Mw) 1,230 1,370 2,0104,950 16,500 10,900 36,500 29,000 76,500 68,600 91,500 215,000 145,500527,000 1,253,000 3,220,000

Example 21A Rapid Size-Exclusion Chromatography—First Conditions

In a first experiment, molecular weight was determined with asample-throughput of 70 seconds per sample.

Briefly, the mobile-phase solvent was trichlorobenzene at a flowrate of9 ml/min. Sample preparation (dissolution in trichlorobenzene) waseffected on each succeeding sample while each preceding sample was beingseparated. The polymer samples were serially injected at 70 secondintervals (with overlaid injection). The transfer line for transferringthe samples to the ELSD was maintained at about 165° C. The samples orcomponents thereof were detected with an ELSD detector at 180° C.(nebulizer temperature)/250° C. (evaporator temperature) and 1.8 l/minof nitrogen.

FIGS. 18A and 18B show the results as a chromatograph for thepolystyrene standards overlaid as a single trace (FIG. 18A) and as acalibration curve for representative polyethylene standards (FIG. 18B).Linearity of the calibration curve is demonstrated.

Example 21B Rapid Size-Exclusion Chromatography—Second Conditions

In a second experiment, molecular weight was determined with asample-throughput of 2¼ minutes per sample.

Briefly, the mobile-phase solvent was o-dichlorobenzene at a flowrate of10 ml/min. Sample preparation (dissolution in trichlorobenzene) waseffected on each succeeding sample while each preceding sample was beingseparated. The polymer samples were serially injected at 2.2 minuteintervals (without overlaid injection). The transfer line fortransferring the samples to the ELSD was maintained at about 160° C. Thesamples or components thereof were detected with an ELSD detector at160° C. (nebulizer temperature)/250° C. (evaporator temperature) and 2.0l/min of nitrogen.

FIGS. 19A and 19B show the results as a chromatograph for representativepolystyrene standards and polyethylene standards overlaid as a singletrace (FIG. 19A) and as a calibration curve for representativepolyethylene standards (FIG. 19B). Linearity of the calibration curve isdemonstrated.

Example 22 High-Temperature HPLC with Mobile-Phase Temperature Gradient

This example demonstrates the principle for high-temperaturecharacterization of a polyethylene polymer sample using liquidchromatography with a mobile-phase temperature gradient.

A single, short, high-aspect ratio column (0.8 cm×5 cm) contained apolystyrene monolith as the separation medium and resided in a PL-210HT-GPC oven maintained at 140° C. The system was configuredsubstantially as shown in FIG. 6 and described in connection therewithand as follows. Two mobile-phase reservoirs 114, 120 were provided andequipped with two Waters 515 pumps 116, 118. A “mobile-phase A”reservoir 114 feeding pump 116 (hereinafter “pump A”) comprisedtrichlorobenzene (TCB) and, in operation, was configured to pumpmobile-phase A through the injection valve 210 (100) and through theoven, whereby the mobile-phase A was heated to become the hot mobilephase (i.e., hot TCB). A “mobile-phase B” reservoir 120 feeding pump 118(hereinafter “pump B”) also comprised trichlorobenzene, and inoperation, was configured to pump mobile-phase B to bypass most of theheated environment, and to enter the oven immediately prior to thecolumn 102 as an essentially ambient-temperature mobile phase (i.e.,cold TCB). Detection was effected with a PD 2000 light-scatteringdetector (90°).

In a first experiment, a polyethylene polymer sample (M_(w)=30,000) wasintroduced into the system with mobile-phase A (only) at a flow rate of3 ml/min, such that the sample entered the column with the hot TCBmobile phase. The mobile-phase was maintained as the hot TCB during theentire experiment.

In a second experiment, a polyethylene polymer sample (M_(w)=30,000) wasintroduced into the system with mobile phase initially configured asmobile-phase B at a flow rate of 3 ml/min, such that the sample enteredthe column with the cold TCB mobile phase. The mobile-phase wasmaintained as the cold TCB for two minutes, at which time the system wasreconfigured to switch to mobile-phase B at 3 ml/min such that thesample was eluted shortly thereafter with hot TCB—essentially effectinga mobile-phase temperature step-gradient (from cold TCB to hot TCB).

FIG. 20 shows the chromatograph—superimposed (overlaid) for the firstand second experiments. Comparison of the two traces demonstrates thatelution of the polyethylene sample was effectively controlled bycontrolling the temperature of the mobile phase. Hence, mobile-phasetemperature gradients can be employed in connection with thehigh-temperature characterization of polymers.

Example 23 Very Rapid Flow-Injection Light-Scattering

This example demonstrates the characterization of polymer library usinga very rapid flow-injection light-scattering (FILS) system. The samplethroughput was 8 seconds per sample. This example also demonstrates theadvantage of using a low-molecular weight insensitive detector,particularly an ELSD, over a static light-scattering (SLS) detector(90°) in such a FILS system. This example demonstrates, moreover, thatthe data from an entire 96-member library of polymer samples can becollected, processed and then stored in a single data file.

A 96-member polymer library was introduced into a flow-injectionlight-scattering system configured substantially as shown in FIG. 7C anddescribed in connection therewith—with a 0.2 μl in-line filter in place,but no chromatographic column. The polymer samples were seriallyinjected at intervals of 8 seconds into a methyl-tert-Butyl Ether mobilephase at a flow rate of 4 ml/min.

In a first experiment, the polymer samples were detected with a 90° SLS(using Wyatt's MiniDawn). In a second experiment, the polymer sampleswere detected with an ELSD (PL-1000) at 50° C. and 1.5 l/min gasflowrate. In both the first and second experiments, the data for theentire polymer library (96 samples) was collected and stored as a singledata file (in about 13 minutes total cumulative time).

FIGS. 21A and 21B show the resulting chromatographs for the 96 polymersamples using the SLS detector (FIG. 21A) and the ELSD (FIG. 21B).Comparison of these chromatographs demonstrates that the ELSD was ableto differentiate between various polymer samples of the library with asample-throughput of 8 seconds per sample.

Example 24 Variable-Flow Light-Scattering

This example demonstrates variable-flow light scattering approaches forcharacterizing a library of methacrylate emulsion polymers prepared bybatch free-radical emulsion polymerization. The sample-throughput was 35seconds per sample.

The flow-injection analysis system was substantially as shown in FIG. 7Cand described in connection therewith. Specifically, the system includedan eight-port injection valve 210 (Valco Instruments), an HPLC pump 116(Waters 515), stainless steel capillaries, an in-line filter 212 (2 μm,Valco Instruments), and a combined SLS/DLS/RI flow-through detector(Precision Detectors, PD2000/QELS)—with no chromatographic column.

The system was calibrated with monodisperse PS latex standards havingR_(h) of 9.5, 25, 51, and 102 nm in ultrapure water (Duke Scientific,Palo Alto, Calif.).

The emulsion samples were prepared (substantially in the mannerdescribed in Example 17) by dilution with ultrapure water to aconcentration of about 0.001 wt % using an auto-sampler substantially asshown in FIG. 4 and described in connection therewith. The emulsionpolymer samples (20 μl) were serially injected into an ultra-pure watermobile phase at intervals of 35 seconds. The mobile-phase flow rate wascontrolled by the pump 116 which, in turn, was controlled bymicroprocessors 350, 352, to provide an advancing flowrate, V_(ADVANCE)of 1.5 l/min that advanced the sample into the detection cavity of thelight-scattering cell very rapidly—within about a few seconds. Thestatic light-scattering detector signal was monitored as an indicationof the leading edge of the sample entering the detection cavity. Anincrease of the static light-scattering detector signal to 2.5 V abovethe baseline voltage caused the microprocessor to reduce the flowrate ofthe mobile phase to a detection flow rate V_(DETECT) of 0.1 ml/min,which was subsequently maintained for a detection period of 15 seconds.

During this detection period, dynamic light-scattering measurements weretaken at a temperature of 35° C. using the correlator board of thePD2000/QELS instrument (Software NTP32, version 0.98.005) as follows: 10μsec sampling times; dilation factor of 4; and a total measurement timeof 1.5 seconds per data point. Hence, 10 independent measurements ofR_(h) were taken per sample during the 15 second detection period.

Following the detection period, the flow-rate was increased to a passingflowrate, V_(PASS) of 1.5 l/min—the same as the advancing flowrate,V_(ADVANCE) for a period of about 15 seconds. The whole cycle,represented schematically in FIG. 7D, was then repeated for each of thepolymer samples.

The post-acquisition data analysis and processing for the polymerlibrary was performed automatically. To ensure that measurementscorresponded to a particular sample in the detection cavity (i.e., inthe scattering volume), measurements taken during the detection periodare only considered for further processing and analysis when the SLSsignal clearly exceeds the aforementioned baseline voltage. From thoseconsidered measurements, the first 3 measurements taken during thedetection period were discarded to ensure that uniform flow-conditionshad been established with respect to the processed data. The R_(h) for asingle measurement point for the sample were then determined byaveraging the remaining 7 individual measurements and removing erroneousspikes and noise, where applicable.

The determined hydrodynamic radius R_(h) (nm) for each of the members ofthe emulsion library are shown in Table 18.

TABLE 18 Determined Average R_(h) (nm) for Emulsion Library 1 2 3 4 5 67 8 9 10 11 12 A 40.3 43.8 48.3 50.6 50.4 56.5 56.6 56.6 54.1 56.9 56.961.6 B 48.3 51.8 52.5 53.4 54.0 55.4 54.7 53.8 59.4 59.8 50.9 48.7 C53.1 53.8 54.2 54.2 55.9 55.0 56.4 61.0 55.1 52.4 47.2 48.2 D 52.6 53.956.1 55.4 56.0 60.7 57.6 56.0 48.9 50.7 49.4 47.8 E 56.3 55.7 56.4 56.955.5 57.7 54.8 52.4 51.4 50.9 48.7 49.3 F 56.7 56.5 57.2 62.4 55.3 54.052.2 51.9 53.0 49.9 50.2 49.4 G 56.8 59.7 59.3 57.9 54.5 52.9 50.3 48.448.8 46.7 51.3 50.1 H 63.3 61.5 58.7 58.9 52.7 52.4 52.4 49.1 50.3 48.847.6 48.4

Example 25 Single-Shot Indirect Calibration

This example demonstrates single-shot indirect calibration of a liquidchromatography system.

Conventional Commercially-Available Calibration Standards

FIG. 22A shows the chromatograph resulting from single-shot calibrationusing eight pooled, commercially-available polyisobutylene standards(FIG. 22A).

Although the commercially available standards employed were eachconsidered to be and were sold as “narrow-band” standards, FIG. 22Ademonstrates that the polyisobutylene standards could not be effectivelyemployed in single-shot (pooled standard) calibration. As shown therein,the chromatograph shows only three broad peaks—without resolution of atleast five of the polyisobutylene standards.

Single-Shot Calibration Standards for Polyisobutylene

Because a single-shot calibration is generally advantageous with respectto system accuracy, expense and speed, a set of polystyrene standardssuitable for use, when pooled, as a single-shot standards forpolyisobutylene were developed as follows.

A set of nine commercially available polyisobutylene standards havingknown molecular weights were individually and serially characterizedwith the liquid chromatography system (in toluene and under the sameconditions) to determine the retention time of the individual standards.The nine polyisobutylene standards and their corresponding (known)molecular weight were:

Polyisobutylene Standards (M_(peak))

(1) 1000

(2) 4,000

(3) 9,500

(4) 26,000

(5) 67,000

(6) 202,500

(7) 539,500

(8) 1,300,000

(9) 3,640,000

After all of the standards had been run individually through the system(nine runs total), the data was assembled to form an absolutepolyisobutylene (PIB) calibration based on the individual runs. FIG. 23Ashows the individually determined retention-time data plotted againstthe corresponding known molecular weight—referred to herein as an“absolute” or “direct” polyisobutylene (PIB) calibration curve. The datafor each of the PIB standards ((1) through (9)) are labeled on thechromatograph.

A set of commercially available polystyrene standards having knownmolecular weights were then evaluated with the same system under thesame conditions (data not shown). Those polystyrene standards havingretention times that were substantially the same as the retention timesfor the nine PIB standards were selected, with the resulting correlationbeing as follows:

Polyisobutylene Standards Selected Polystyrene Standards (M_(peak))(M_(peak)) (1) 1000 (1) 1,350 (2) 4,000 (2) 4,950 (3) 9,500 (3) 10,850(4) 26,000 (4) 28,500 (5) 67,000 (5) 70,600 (6) 202,500 (6) 214,500 (7)539,500 (7) 520,000 (8) 1,300,000 (8) 1,296,000 (9) 3,640,000 (9)3,220,000

A set of eight of the nine selected polystyrene (PS) standards were thenpooled to form a set of polystyrene standards (the small molecularweight standard being omitted), that were, effectively, a compositionsuitable for single-shot indirect calibration for polyisobutylene. Thesepooled PS standards were then characterized with the chromatographysystem with the same conditions. FIG. 22B shows the resultingchromatograph for the set of eight, pooled polystyrene standards thatcorrespond to (i.e., have the same hydrodynamic volume as) the PIBstandards of known molecular weight. As expected, the indirect PSstandards for PIB are readily resolved by the chromatographic system.Significantly, however, these well-resolved samples arehydrodynamic-volume equivalents of the eight PIB standards that couldnot be resolved by the system when loaded as a single shot. (See FIG.22A, and compare to FIG. 22B).

The aforementioned steps were repeated in substantially the same mannerwith the same system for a second set of polyisobutylene standards ofknown (different) molecular weights.

An indirect PIB calibration curve was then formed, by plotting theretention time determined from the single-shot run with the pool of theselected polystyrene standards—against the molecular weight of thecorresponding polyisobutylene standards. FIG. 23B shows the indirect PIBcalibration curve. Comparison of FIG. 23A (absolute PIB calibrationcurve) and FIG. 23B (indirect PIB calibration curve) demonstrates thatthe calibration curve determined from the single-shot indirectcalibration standards for polyisobutylene is equivalent to thecalibration curve laboriously derived from the serial direct calibrationof the PIB standards.

Example 26 Parallel Characterization of Polymers with Dynamic LightScattering

This example demonstrates the characterization of a 96-member library ofemulsion polymers in a parallel manner—using a plurality of dynamiclight-scattering (DLS) detector probes. Because the number of DLS probeswas less than the total number of samples, the library was evaluated ina serial-parallel (i.e., semi-parallel) manner. The averagesample-throughput for characterizing the entire library in this mannerwas about 5-15 seconds per sample.

The emulsion library was the same as used in connection with Example 24,and was prepared (diluted) as described therein. No filtering wasperformed on the dispersion before the measurements.

A parallel DLS system used for characterizing the library of polymersamples was configured substantially as shown in FIG. 24 and describedin connection therewith. Briefly, the system comprised an array 410 oftwo DLS probes 420 supported in parallel by a common support structure.Each probe 420 included a transmitting optical fiber 425, 425′ and areceiving optical fiber 430, 430′.

Two single-mode fiber couplers, also referred to as optics (not shown),were used for transmitting an incident light and collecting a scatteredlight. These couplers consisted of a gradient refractive index (GRIN)lens aligned to a single-mode optical fiber. (Such couplers aretypically used for coupling the output of a laser diode into an opticalfiber.). For the DLS application, a focal length of 10 mm for bothsource and detector optics were chosen. The optics were mounted at anangle of 45 degrees with respect to each other giving a measurementangle of 135 degrees.

A HeNe laser 435 provided laser light at 632.8 nm wavelength (5 mW,Melles Griot). The laser light was coupled into the transmitting opticalfiber in the fiber-optics array 440 and delivered into the sample 20 bythe first optic. The scattered light was collected by the second optic.Unlike the immersed-probe configuration shown in FIG. 24, themeasurements were done in a non-immersion, non-contact mode by mountingthe probes approximately 5 mm above the liquid surface, such that thelaser beam was delivered and the scattered light was collected throughthe liquid surface.

The scattered light collected by the second optic was coupled into thereceiving optical fiber. The receiving optical fiber was connected to anavalanche photodiode (SPCM, EG&G, Canada). Measurements were performedat a temperature of 21° C. The measurements and photon autocorrelationwere taken in a serial manner with a data acquisition time of 5 secondsper sample using a commercial autocorrelator board (ALV 5000/E, ALV GmbHLangen, Germany). The autocorrelation function was analyzed by a secondorder cumulant analysis (ALV Software, Version 2.0) and the hydrodynamicradius R_(h) and the polydispersity index (PDI) were determined.

These data are presented in Tables 19 and 20, respectively. A comparisonof Table 19 with Table 18 (Ex. 24) demonstrates that the averagehydrodynamic radii determined by this parallel DLS, non-immersiondetection approach correlate well with those values determined byvariable flow-injection analysis.

Including time for positioning the sample under the probe, the totalmeasurement took between 5 and 15 seconds per well.

TABLE 19 Determined Average R_(h) (nm) for Emulsion Polymer Library 1 23 4 5 6 7 8 9 10 11 12 A 38.8 40.4 45.9 46.4 49.5 48.9 50.1 56.2 50.151.9 53.2 54.8 B 43.8 48.1 52.7 50.6 50.9 52.5 52.1 51.3 54.8 55.8 48.545.2 C 48.5 50.4 51.8 50.3 53.2 51.2 54.1 59.2 54.3 49.3 48.3 47.2 D50.5 52.2 52.9 51.7 52.9 58.1 59.2 53.9 49.1 50.8 48.6 46.2 E 56.0 53.654.7 55.0 58.7 56.3 52.6 48.6 47.0 49.1 47.5 48.4 F 51.0 54.2 56.2 61.054.2 50.9 50.9 52.2 49.0 50.3 46.8 48.2 G 53.8 55.5 56.3 53.6 53.1 52.849.4 45.6 48.9 43.8 45.7 48.2 H 58.2 56.1 54.8 55.1 50.7 49.1 49.4 47.149.6 44.7 44.4 46.3

TABLE 18 Determined PDI (cumulant analysis) for Emulsion Polymer Library1 2 3 4 5 6 7 8 9 10 11 12 A 0.08 0.08 0.03 0.03 0.01 0.09 0.08 0.060.06 0.02 0.11 0.05 B 0.09 0.14 0.25 0.11 0.15 0.07 0.15 0.13 0.04 0.040.02 0.12 C 0.08 0.01 0.01 0.01 0.06 0.07 0.05 0.11 0.02 0.02 <0.01 0.06D 0.06 0.08 0.03 0.09 0.06 0.02 0.12 0.09 0.05 0.01 <0.01 0.08 E 0.090.08 0.03 0.03 0.13 0.04 0.01 0.01 0.02 0.06 0.01 0.02 F <0.01 0.03 0.030.08 0.07 0.03 0.04 0.03 0.11 0.06 0.04 0.07 G 0.08 0.08 0.06 0.06 0.060.09 0.05 <0.01 0.09 0.10 0.12 0.09 H 0.05 0.06 0.01 0.06 0.05 0.05 0.100.01 0.15 <0.01 0.14 0.09

In light of the detailed description of the invention and the examplespresented above, it can be appreciated that the several objects of theinvention are achieved.

The explanations and illustrations presented herein are intended toacquaint others skilled in the art with the invention, its principles,and its practical application. Those skilled in the art may adapt andapply the invention in its numerous forms, as may be best suited to therequirements of a particular use. Accordingly, the specific embodimentsof the present invention as set forth are not intended as beingexhaustive or limiting of the invention.

We claim:
 1. A method for characterizing a plurality of non-biologicalpolymer samples, the method comprising serially injecting four or morenon-biological polymer samples into a mobile-phase of a flow-injectionanalysis system, and detecting a property of the injected samples or ofcomponents thereof with a continuous-flow light-scattering detector. 2.The method of claim 1 wherein the plurality of polymer samples arecharacterized with an average sample-throughput of not more than about10 minutes per sample.
 3. The method of claim 1 wherein the plurality ofpolymer samples are characterized with an average sample-throughput ofnot more than about 4 minutes per sample.
 4. The method of claim 1wherein the plurality of polymer samples are characterized with anaverage sample-throughput of not more than about 1 minute per sample. 5.The method of claim 1 wherein a property of the injected samples or ofcomponents thereof is detected using a static light-scattering detector.6. The method of claim 1 wherein a property of the injected samples orof components thereof is detected using a dynamic light-scatteringdetector.
 7. The method of claim 1 wherein a property of the injectedsamples or of components thereof is detected using an evaporativelight-scattering detector.
 8. The method of claim wherein a property ofthe injected samples is detected using two or more detectors.
 9. Themethod of claim 1 wherein the polymer samples are selected from thegroup consisting of polymer solutions, polymer emulsions and polymerdispersions.
 10. The method of claim 1 wherein the four or more polymersamples are members of a library of polymerization product mixtures. 11.The method of claim 1 wherein the four or more polymer samples comprisea polymer component, a monomer component and a continuous fluid phase.12. The method of claim 1 wherein the four or more polymer samplescomprise a copolymer component, a first comonomer component, a secondcomonomer component and a continuous fluid phase.
 13. The method ofclaim 1 further comprising filtering the injected samples beforedetection.
 14. A method for characterizing a plurality of non-biologicalpolymer samples, the method comprising injecting a first polymer sampleinto the mobile phase of a flow-injection analysis system at a firstinjection time, t_(FII1), detecting light scattered from the injectedfirst sample or a component thereof in a continuous-flowlight-scattering detector, injecting a second polymer sample into themobile phase of the flow-injection analysis system at a second injectiontime, t_(FII2), and detecting light scattered from the injected secondsample or a component thereof in the continuous-flow light-scatteringdetector.
 15. The method of claim 14 wherein the flow-injection cycletime, T_(FI), delineated by the difference in time, t_(FII2)−t_(FII1),is not more than about 10 minutes.
 16. The method of claim 14 whereinthe flow-injection cycle time, T_(FI), delineated by the difference intime, t_(FII2)−t_(FII1), is not more than about 4 minutes.
 17. Themethod of claim 14 wherein the flow-injection cycle time, T_(FI),delineated by the difference in time, t_(FII2)−t_(FII1), is not morethan about 1 minute.